user17191: I have this misunderstanding about love and attachment as they relate to one another. It's hard to put in words, so I'll try with some examples first.
My understanding is that love is something you give away without expecting anything in return. While love where you need or want something from the other person (like for example, expect that other person to make you happy, or you want to control the other person in some way, or try to change them to be more of how you would want them to be, etc) is actually attachment.
One example of true love I can think of is love for your children. You love them unconditionally. You understand they are their own person, with their own dreams, aspiration, thoughts, etc, so whatever they do, good or bad, you support them, help them, etc. You don't try to change them, or influence them, or impose your ideas on them, or have them accomplish the things you couldn't (e.g. I couldn't go to med school, but my child will), etc. No matter what happens, you love them because they are your children, and you love them no matter what they do.
Taking that further, even in the presence of death, I still can understand love (at least I think I do). Everyone dies. Your children might die. And even if you love them and will miss them if they are gone, or suffer after they are gone, that suffering doesn't linger. You continue to love your children even after they are gone (or at least the idea of them or the memory of them).
But here is another example. You love your partner. You think you love them like in the example above. But then they cheat on you with some other person. If you loved your partner unconditionally, you would be OK with that... I think. If being with someone else makes them happy, you should be happy for them, right? But in most relationships, you expect from your partner that they don't cheat on you, or to behave in a certain way. When that expectation is broken, you suffer. Arguments start, resentment, maybe violence towards that person. Is this because of attachment to the person and not love? Because we expect them, and demand, that they behave in a way that doesn't hurt us or make us suffer, that we are attached to the idea that your partner is only ours to have?
So I guess, my question is this: What is love and what is attachment in a relation with your partner? What happens to love and attachment when they cheat with someone else? (for most of the people I know, death is less painful than being cheated upon; suffering caused by death eventually heals, but being cheated upon lingers for much longer).
Can you truly love someone with no attachment so that no matter what they do, you do not end up suffering?

user11009: Buddhism teaches compassion instead of love:
==============
Compassion (karuṇā) has the nature of being moved by the suffering of others. The sadness we might experience over the suffering or loss of a loved one is not true compassion. Such sadness is sentimental, a manifestation of grief. Real compassion arises when the mind, detached from self-referential concerns, is stirred by the suffering of others, feeling the suffering as its own.
https://www.accesstoinsight.org/lib/authors/mendis/wheel322.html

user13375: Don’t worry, almost everyone is very confused about love and what it is. We confuse it and bind it up with other emotions both negative and positive and this is what causes the confusion.
Fortunately, real love is simple and clear to define and once you understand what it really is you can begin to unravel all the confusion.
Love is nothing more than the wish for another to have happiness.
That’s it. Really. It is that simple.
It is defined as one of the four immeasurable minds which we should practice and develop.  And now that you know what love is... I will tell you what compassion is.
Compassion is nothing more than the wish for another to be free from suffering.
Again, very simple and clear and another of the four immeasurables. And you will notice that love and compassion are like flip sides of the same coin.
All the rest that we normally associate with “love” and “compassion” are just confusions of other emotions usually involving attachment and/or aversion.
In your question you cite examples of love that people feel for there partners and/or children. Most people do genuinely love  both their children and partners, but also feel all kinds of attachment and desire and wants and other non-virtuous emotions towards them as well. Once you are clear on what real love is ... see above ... then the question becomes what are these other emotions we associate so often with love and what is the nature of them? Are they virtuous? Non-virtuous? Do they cause happiness in ourselves or others? Suffering? Like that...

user8157: If one is in an intimate relationship with another person, one is attached to them. The Piyavagga says: 


From endearment springs grief, from endearment springs fear. For one who is wholly free from endearment there is no grief, whence then
  fear?
From affection springs grief, from affection springs fear. For one who is wholly free from affection there is no grief, whence then
  fear?
From attachment springs grief, from attachment springs fear. For one who is wholly free from attachment there is no grief, whence then
  fear?

https://www.accesstoinsight.org/tipitaka/kn/dhp/dhp.16.budd.html

Above & below, Buddhism teaches any engaging in sensual intimacy is attachment:

Now delight in feelings is clinging/attachment.
https://suttacentral.net/mn38/en/bodhi

One is attached to another person when, if that relationship ends, one feels alone. One feels something missing or incomplete in their life. This sense of loss is called 'hurt'. It is emotionally painful. The Piyavagga says:

From attachment springs grief, from attachment springs fear. For one
  who is wholly free from attachment there is no grief, whence then
  fear?

Buddhism teaches to avoid hurting others, as follows:

This act I am
  doing leads to hurting myself, hurting others, or hurting both. It’s
  unskillful, with suffering as its outcome and result.’ Then, Rāhula,
  you should desist from such a deed.
https://suttacentral.net/mn61/en/sujato

This means 'duty' or 'obligation' in respect to right behaviour is required in relationship (rather than 'unconditional love'). For example, the Buddhist scriptures teach a husband has five duties or obligations towards his wife and, upon performing his duty, the wife returns her love in five ways, as follows:

In five ways, young householder, should a wife as the West be
  ministered to by a husband:
(i) by being courteous to her, (ii) by not despising her, (iii) by
  being faithful to her, (iv) by handing over authority to her, (v) by
  providing her with adornments.
The wife thus ministered to as the West by her husband shows her
  compassion to her husband in five ways:
(i) she performs her duties well, (ii) she is hospitable to relations
  and attendants  (iii) she is faithful, (iv) she protects what he
  brings, (v) she is skilled and industrious in discharging her duties.
In these five ways does the wife show her compassion to her husband
  who ministers to her as the West. Thus is the West covered by him and
  made safe and secure.
https://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html 

In other words, the love of a wife & husband, in Buddhism, is conditional. One condition of a husband/wife relationship is each is sexual faithful. 
If husbands & wives are not sexually faithful to each other, the relationship will generally inevitably fall apart. The Samajivina Sutta says:

If both husband & wife want to see one another not only in the present
  life but also in the life to come [in the future], they should be in tune [with each
  other] in conviction, in tune in virtue, in tune in generosity, and in
  tune in discernment. Then they will see one another not only in the
  present life but also in the life to come.
https://www.accesstoinsight.org/tipitaka/an/an04/an04.055.than.html

Therefore, it generally won't help maintain a relationship if one partner attempts to unconditionally love an unfaithful partner. Instead, by attempting unconditional love, one partner is often enabling the bad habits of the unfaithful partner. The scriptures call such a situation "wretchedness", as follows:

Here, the husband is one who destroys life, takes what is not given, engages in sexual misconduct, speaks falsely, and indulges in liquor, wine, and intoxicants, the basis for heedlessness; he is immoral, of bad character; he dwells at home with a heart obsessed by the stain of miserliness; he insults and reviles ascetics and brahmins... but his wife is virtuous,
  charitable, generous. She is a female deva (goddess; angel) living with a wretched
husband.
https://suttacentral.net/an4.53/en/bodhi

At least in relation to a wife, the scriptures say an immoral wife can be expelled from the family home of the husband, as follows: 

If a female has the powers of attractiveness, wealth, relatives, and
  children, but not that of ethical behavior, the family will send her
  away, they won’t accommodate her.
https://suttacentral.net/sn37.30/en/sujato

Similarly, Buddhism teaches parents have five duties towards their children, which include restraining their children from doing evil (harmful/hurtful) things and nurturing their children to do good. It follows the love of parents towards their children in Buddhism is not unconditional. It is conditional, as follows:

In five ways, young householder, the parents thus ministered to as the
  East by their children, show their compassion:
(i) they restrain them from evil, (ii) they encourage them to do good,
  (iii) they train them for a profession, (iv) they arrange a suitable
  marriage, (v) at the proper time they hand over their inheritance to
  them.
In these five ways do children minister to their parents as the East
  and the parents show their compassion to their children. Thus is the
  East covered by them and made safe and secure.
https://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html

For example, if a child wishes to engage in drug taking, sexual orgies & other evil deeds in the family home, the duty of parents is to restrain their children. It is not to unconditionally love children so the children of the family are free to take drugs & have sexual orgies in the family home.  
For example, in the scriptures, there is the story about an unethical misbehaved wife. The Buddha, who was visiting the family home, tamed the wife, as follows: 

Householder, what’s with the people making that dreadful racket in
  your home? You’d think it was fishermen hauling in a catch!
Sir, that’s my daughter-in-law Sujātā. She’s been brought here from a
  wealthy family.She doesn’t obey her mother-in-law or father-in-law or
  her husband. And she does not honor, respect, esteem and venerate the
  Buddha.
Then the Buddha addressed Sujātā, saying, “Come, Sujātā.”
“Yes, sir,” she replied. She went up to the Buddha, bowed, and sat
  down to one side. The Buddha said to her:....
https://suttacentral.net/an7.63/en/sujato

In conclusion, there appear to be no teachings in the Buddhist scriptures that say, in the context of vital co-dependent social relationships, you can truly love someone with no attachment so that no matter what they do you do not end up suffering. 
The Metta Sutta, about unconditional love, says: 

This is what should be done   By one who is skilled in goodness, And
  who knows the path of peace...

In other words, the Metta Sutta appears to not recommend the practice of unconditional love to those who are not skilled in goodness. 

user43: Love is loving (=accepting) as is. "As is" means, without condition or boundary like "only when". 
Love that adores one thing and rejects the other is not real love "as is", it is attachment or preference. Love that divides the world into the loved and the unloved is not real love, it is attachment or preference.
Real love is Nirvana. I know this is hard for you to understand. Let me elaborate. Real love is loving everything as is, without aversion, without boundaries. Love is the true nature of mind. When mind is free from attachment, aversion, confusion - what remains is suchness, also known as love.

user254: When is it love?
There's Buddhist doctrine about the brahmaviharas which are three different kinds of love ...

I hope you're well
I don't want to hurt you
I rejoice in your virtue/success

... plus equanimity as the fourth.
If you loved your partner unconditionally, you would be OK with that
In the old days before "no-fault divorce" people (in Anglophone countries) used to sue each other for adultery: and the alleged "damage" used to include Alienation of affections.
I think the theory was that if your partner was adulterous then you'd be receiving less affection from them -- an affection which should have been, as their spouse, rightfully yours.
And I think that contradicts your premise, i.e.

My understanding is that love is something you give away without expecting anything in return.

I think another Buddhist theme is that, you do things because they (actions/intentions) are morally right or virtuous. Conversely you don't do things just because you feel like it (e.g. presumably shouldn't hurt people if or because you feel angry).
Because we expect them, and demand, that they behave in a way that doesn't hurt us or make us suffer, that we are attached to the idea that your partner is only yours to have?
I guess that -- expecting behaviour -- might work if you can form a contract, have a meeting of minds, with a sane and reliable partner.
Conversely some people (sometimes children) don't like conforming to other people's expectations.
With such a one, unreliable, a possible winning strategy might be (I don't know if this is applicable to you, feasible, or Buddhist -- but based on experience) if they ask e.g., "What do you expect me to do here?", reply, "I don't expect you to do anything. You can do..."
Then provide a safe environment, where they can't easily hurt themselves. And the necessities of life. And age-appropriate toys or tools. And good friends, some enjoyable group/social activities -- role models.
I think that behaviour/misbehaviour is partly conditioned/dependent -- if somebody is seeking some liberation then perhaps it's wise to ensure their environment is moral, safe, sane, unoppressive and with opportunities for them to be or to become good friends themselves.
Can you truly love someone with no attachment so that no matter what they do, you do not end up suffering?
I think so if you're semi-enlightened.
You suggested already that you can have children without their causing your suffering.
If I know children, they'll transgress in various ways, large or small -- and you're probably supposed to interact with them and correct their behaviour -- maybe without stopping-loving them though.
There's some doctrine here about choosing a spouse or partner, for what that's worth -- preferably one who is equal.
I think that a or the key to "not suffering" is to behave ethically. There's a sutta Kimattha Sutta: What is the Purpose? (AN 11.1) which begins ...

I have heard that on one occasion the Blessed One was staying near Savatthi in Jeta's Grove, Anathapindika's monastery. Then Ven. Ananda went to the Blessed One and on arrival, having bowed down to him, sat to one side. As he was sitting there he said to the Blessed One: "What is the purpose of skillful virtues? What is their reward?"
"Skillful virtues have freedom from remorse as their purpose, Ananda, and freedom from remorse as their reward."
"And what is the purpose of freedom from remorse? What is its reward?"
"Freedom from remorse has joy as its purpose, joy as its reward."
"And what is the purpose of joy? What is its reward?"
"Joy has etc.

I equate that "freedom from remorse" with non-suffering -- "I do not regret it".
See for example Sīlānussati
In context I think that an example of sīlānussati might be Akkosa Sutta: Insult (SN 7.2) where the buddha seems to be happy.
In my experience that happiness might be in retrospect, i.e. good behaviour now leads to "joy" later.
See also What is the basis?

17191: <p>I have this misunderstanding about love and attachment as they relate to one another. It's hard to put in words, so I'll try with some examples first.</p>

<p>My understanding is that love is something you give away without expecting anything in return. While love where you need or want something from the other person (like for example, expect that other person to make you happy, or you want to control the other person in some way, or try to change them to be more of how you would want them to be, etc) is actually attachment.</p>

<p>One example of true love I can think of is love for your children. You love them unconditionally. You understand they are their own person, with their own dreams, aspiration, thoughts, etc, so whatever they do, good or bad, you support them, help them, etc. You don't try to change them, or influence them, or impose your ideas on them, or have them accomplish the things you couldn't (e.g. I couldn't go to med school, but my child will), etc. No matter what happens, you love them because they are your children, and you love them no matter what they do.</p>

<p>Taking that further, even in the presence of death, I still can understand love (at least I think I do). Everyone dies. Your children might die. And even if you love them and will miss them if they are gone, or suffer after they are gone, that suffering doesn't linger. You continue to love your children even after they are gone (or at least the idea of them or the memory of them).</p>

<p>But here is another example. You love your partner. You think you love them like in the example above. But then they cheat on you with some other person. If you loved your partner unconditionally, you would be OK with that... I think. If being with someone else makes them happy, you should be happy for them, right? But in most relationships, you expect from your partner that they don't cheat on you, or to behave in a certain way. When that expectation is broken, you suffer. Arguments start, resentment, maybe violence towards that person. Is this because of attachment to the person and not love? Because we expect them, and demand, that they behave in a way that doesn't hurt us or make us suffer, that we are attached to the idea that your partner is only ours to have?</p>

<p>So I guess, my question is this: What is love and what is attachment in a relation with your partner? What happens to love and attachment when they cheat with someone else? (for most of the people I know, death is less painful than being cheated upon; suffering caused by death eventually heals, but being cheated upon lingers for much longer).</p>

<p>Can you truly love someone with no attachment so that no matter what they do, you do not end up suffering?</p>
 11009: <p>Buddhism teaches compassion instead of love:</p>

<p>==============</p>

<p>Compassion (<a href="https://en.wikipedia.org/wiki/Karu%E1%B9%87%C4%81" rel="nofollow noreferrer">karuṇā</a>) has the nature of being moved by the suffering of others. The sadness we might experience over the suffering or loss of a loved one is not true compassion. Such sadness is sentimental, a manifestation of grief. Real compassion arises when the mind, detached from self-referential concerns, is stirred by the suffering of others, feeling the suffering as its own.</p>

<p><a href="https://www.accesstoinsight.org/lib/authors/mendis/wheel322.html" rel="nofollow noreferrer">https://www.accesstoinsight.org/lib/authors/mendis/wheel322.html</a></p>
 13375: <p>Don’t worry, almost everyone is very confused about love and what it is. We confuse it and bind it up with other emotions both negative and positive and this is what causes the confusion.</p>

<p>Fortunately, real love is simple and clear to define and once you understand what it really is you can begin to unravel all the confusion.</p>

<p><b><em>Love is nothing more than the wish for another to have happiness.</em></b></p>

<p>That’s it. Really. It is that simple.</p>

<p>It is defined as one of the four immeasurable minds which we should practice and develop.  And now that you know what love is... I will tell you what compassion is.</p>

<p><b><em>Compassion is nothing more than the wish for another to be free from suffering.</em></b></p>

<p>Again, very simple and clear and another of the four immeasurables. And you will notice that love and compassion are like flip sides of the same coin.</p>

<p>All the rest that we normally associate with “love” and “compassion” are just confusions of other emotions usually involving attachment and/or aversion.</p>

<p>In your question you cite examples of love that people feel for there partners and/or children. Most people do genuinely love  both their children and partners, but also feel all kinds of attachment and desire and wants and other non-virtuous emotions towards them as well. Once you are clear on what real love is ... see above ... then the question becomes what <em>are</em> these other emotions we associate so often with love and what is the nature of them? Are they virtuous? Non-virtuous? Do they cause happiness in ourselves or others? Suffering? Like that...</p>
 8157: <p>If one is in an intimate relationship with another person, one is attached to them. The Piyavagga says: </p>

<blockquote>
  <ol start="212">
  <li><p>From endearment springs grief, from endearment springs fear. For one who is wholly free from endearment there is no grief, whence then
  fear?</p></li>
  <li><p>From affection springs grief, from affection springs fear. For one who is wholly free from affection there is no grief, whence then
  fear?</p></li>
  <li><p>From attachment springs grief, from attachment springs fear. For one who is wholly free from attachment there is no grief, whence then
  fear?</p></li>
  </ol>
  
  <p><a href="https://www.accesstoinsight.org/tipitaka/kn/dhp/dhp.16.budd.html" rel="nofollow noreferrer">https://www.accesstoinsight.org/tipitaka/kn/dhp/dhp.16.budd.html</a></p>
</blockquote>

<p>Above &amp; below, Buddhism teaches any engaging in sensual intimacy is attachment:</p>

<blockquote>
  <p>Now delight in feelings is clinging/attachment.</p>
  
  <p><a href="https://suttacentral.net/mn38/en/bodhi" rel="nofollow noreferrer">https://suttacentral.net/mn38/en/bodhi</a></p>
</blockquote>

<p>One is attached to another person when, if that relationship ends, one feels alone. One feels something missing or incomplete in their life. This sense of loss is called 'hurt'. It is emotionally painful. The Piyavagga says:</p>

<blockquote>
  <p>From attachment springs grief, from attachment springs fear. For one
  who is wholly free from attachment there is no grief, whence then
  fear?</p>
</blockquote>

<p>Buddhism teaches to avoid hurting others, as follows:</p>

<blockquote>
  <p>This act I am
  doing leads to hurting myself, hurting others, or hurting both. It’s
  unskillful, with suffering as its outcome and result.’ Then, Rāhula,
  you should desist from such a deed.</p>
  
  <p><a href="https://suttacentral.net/mn61/en/sujato" rel="nofollow noreferrer">https://suttacentral.net/mn61/en/sujato</a></p>
</blockquote>

<p>This means 'duty' or 'obligation' in respect to right behaviour is required in relationship (rather than 'unconditional love'). For example, the Buddhist scriptures teach a husband has five duties or obligations towards his wife and, upon performing his duty, the wife returns her love in five ways, as follows:</p>

<blockquote>
  <p>In five ways, young householder, should a wife as the West be
  ministered to by a husband:</p>
  
  <p>(i) by being courteous to her, (ii) by not despising her, (iii) by
  <strong>being faithful to her</strong>, (iv) by handing over authority to her, (v) by
  providing her with adornments.</p>
  
  <p>The wife <strong>thus ministered to</strong> as the West by her husband shows her
  compassion to her husband in five ways:</p>
  
  <p>(i) she performs her duties well, (ii) she is hospitable to relations
  and attendants  (iii) <strong>she is faithful</strong>, (iv) she protects what he
  brings, (v) she is skilled and industrious in discharging her duties.</p>
  
  <p>In these five ways does the wife show her compassion to her husband
  who ministers to her as the West. Thus is the West covered by him and
  made safe and secure.</p>
  
  <p><a href="https://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html" rel="nofollow noreferrer">https://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html</a> </p>
</blockquote>

<p>In other words, the love of a wife &amp; husband, in Buddhism, is conditional. One condition of a husband/wife relationship is each is sexual faithful. </p>

<p>If husbands &amp; wives are not sexually faithful to each other, the relationship will generally inevitably fall apart. The Samajivina Sutta says:</p>

<blockquote>
  <p><strong>If both husband &amp; wife want to see one another</strong> not only in the present
  life but also in the life to come [in the future], <strong>they should be in tune [with each
  other]</strong> in conviction, <strong>in tune in virtue</strong>, in tune in generosity, and in
  tune in discernment. Then they will see one another not only in the
  present life but also in the life to come.</p>
  
  <p><a href="https://www.accesstoinsight.org/tipitaka/an/an04/an04.055.than.html" rel="nofollow noreferrer">https://www.accesstoinsight.org/tipitaka/an/an04/an04.055.than.html</a></p>
</blockquote>

<p>Therefore, it generally won't help maintain a relationship if one partner attempts to unconditionally love an unfaithful partner. Instead, by attempting unconditional love, one partner is often enabling the bad habits of the unfaithful partner. The scriptures call such a situation "<strong>wretchedness</strong>", as follows:</p>

<blockquote>
  <p>Here, the husband is one who destroys life, takes what is not given, engages in sexual misconduct, speaks falsely, and indulges in liquor, wine, and intoxicants, the basis for heedlessness; he is immoral, of bad character; he dwells at home with a heart obsessed by the stain of miserliness; he insults and reviles ascetics and brahmins... but his wife is virtuous,
  charitable, generous. She is a female deva (goddess; angel) living with a <strong>wretched</strong>
  <strong>husband</strong>.</p>
  
  <p><a href="https://suttacentral.net/an4.53/en/bodhi" rel="nofollow noreferrer">https://suttacentral.net/an4.53/en/bodhi</a></p>
</blockquote>

<p>At least in relation to a wife, the scriptures say an immoral wife can be expelled from the family home of the husband, as follows: </p>

<blockquote>
  <p>If a female has the powers of attractiveness, wealth, relatives, and
  children, but not that of ethical behavior, the family will send her
  away, they won’t accommodate her.</p>
  
  <p><a href="https://suttacentral.net/sn37.30/en/sujato" rel="nofollow noreferrer">https://suttacentral.net/sn37.30/en/sujato</a></p>
</blockquote>

<p>Similarly, Buddhism teaches parents have five duties towards their children, which include restraining their children from doing evil (harmful/hurtful) things and nurturing their children to do good. It follows the love of parents towards their children in Buddhism is not unconditional. It is conditional, as follows:</p>

<blockquote>
  <p>In five ways, young householder, the parents thus ministered to as the
  East by their children, show their compassion:</p>
  
  <p>(i) <strong>they restrain them from evil</strong>, (ii) <strong>they encourage them to do good</strong>,
  (iii) they train them for a profession, (iv) they arrange a suitable
  marriage, (v) at the proper time they hand over their inheritance to
  them.</p>
  
  <p>In these five ways do children minister to their parents as the East
  and the parents show their compassion to their children. Thus is the
  East covered by them and made safe and secure.</p>
  
  <p><a href="https://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html" rel="nofollow noreferrer">https://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html</a></p>
</blockquote>

<p>For example, if a child wishes to engage in drug taking, sexual orgies &amp; other evil deeds in the family home, the duty of parents is to restrain their children. It is not to unconditionally love children so the children of the family are free to take drugs &amp; have sexual orgies in the family home.  </p>

<p>For example, in the scriptures, there is the story about an unethical misbehaved wife. The Buddha, who was visiting the family home, tamed the wife, as follows: </p>

<blockquote>
  <p>Householder, what’s with the people making that dreadful racket in
  your home? You’d think it was fishermen hauling in a catch!</p>
  
  <p>Sir, that’s my daughter-in-law Sujātā. She’s been brought here from a
  wealthy family.She doesn’t obey her mother-in-law or father-in-law or
  her husband. And she does not honor, respect, esteem and venerate the
  Buddha.</p>
  
  <p>Then the Buddha addressed Sujātā, saying, “Come, Sujātā.”</p>
  
  <p>“Yes, sir,” she replied. She went up to the Buddha, bowed, and sat
  down to one side. The Buddha said to her:....</p>
  
  <p><a href="https://suttacentral.net/an7.63/en/sujato" rel="nofollow noreferrer">https://suttacentral.net/an7.63/en/sujato</a></p>
</blockquote>

<p>In conclusion, there appear to be no teachings in the Buddhist scriptures that say, in the context of vital co-dependent social relationships, you can truly love someone with no attachment so that no matter what they do you do not end up suffering. </p>

<p>The <a href="https://www.accesstoinsight.org/tipitaka/kn/snp/snp.1.08.amar.html" rel="nofollow noreferrer">Metta Sutta</a>, about unconditional love, says: </p>

<blockquote>
  <p>This is what should be done   By one who is skilled in goodness, And
  who knows the path of peace...</p>
</blockquote>

<p>In other words, the Metta Sutta appears to not recommend the practice of unconditional love to those who are not skilled in goodness. </p>
 43: <p>Love is loving (=accepting) <em>as is</em>. "As is" means, without condition or boundary like "only when". </p>

<p>Love that adores one thing and rejects the other is not real love "as is", it is attachment or preference. Love that divides the world into the loved and the unloved is not real love, it is attachment or preference.</p>

<p>Real love is Nirvana. I know this is hard for you to understand. Let me elaborate. Real love is loving everything as is, without aversion, without boundaries. Love is the true nature of mind. When mind is free from attachment, aversion, confusion - what remains is suchness, also known as love.</p>
 254: <p><strong>When is it love?</strong></p>
<p>There's Buddhist doctrine about the <a href="https://www.accesstoinsight.org/search_results.html?q=brahmaviharas" rel="nofollow noreferrer">brahmaviharas</a> which are three different kinds of love ...</p>
<ul>
<li>I hope you're well</li>
<li>I don't want to hurt you</li>
<li>I rejoice in your virtue/success</li>
</ul>
<p>... plus equanimity as the fourth.</p>
<p><strong>If you loved your partner unconditionally, you would be OK with that</strong></p>
<p>In the old days before &quot;no-fault divorce&quot; people (in Anglophone countries) used to sue each other for adultery: and the alleged &quot;damage&quot; used to include <a href="https://en.wikipedia.org/wiki/Alienation_of_affections" rel="nofollow noreferrer">Alienation of affections</a>.</p>
<p>I think the theory was that if your partner was adulterous then you'd be receiving less affection from them -- an affection which should have been, as their spouse, rightfully yours.</p>
<p>And I think that contradicts your premise, i.e.</p>
<blockquote>
<p>My understanding is that love is something you give away without expecting anything in return.</p>
</blockquote>
<p>I think another Buddhist theme is that, you do things because they (actions/intentions) are morally right or virtuous. Conversely you don't do things just because you feel like it (e.g. presumably shouldn't hurt people if or because you feel angry).</p>
<p><strong>Because we expect them, and demand, that they behave in a way that doesn't hurt us or make us suffer, that we are attached to the idea that your partner is only yours to have?</strong></p>
<p>I guess that -- expecting behaviour -- might work if you can form a contract, have a meeting of minds, with a sane and reliable partner.</p>
<p>Conversely some people (sometimes children) don't like conforming to other people's expectations.</p>
<p>With such a one, unreliable, a possible winning strategy might be (I don't know if this is applicable to you, feasible, or Buddhist -- but based on experience) if they ask e.g., &quot;What do you expect me to <em>do</em> here?&quot;, reply, &quot;I don't <em>expect</em> you to do anything. You <em>can</em> do...&quot;</p>
<p>Then provide a safe environment, where they can't easily hurt themselves. And the necessities of life. And age-appropriate toys or tools. And good friends, some enjoyable group/social activities -- role models.</p>
<p>I think that behaviour/misbehaviour is partly conditioned/dependent -- if somebody is seeking some liberation then perhaps it's wise to ensure their environment is moral, safe, sane, unoppressive and with opportunities for them to be or to become good friends themselves.</p>
<p><strong>Can you truly love someone with no attachment so that no matter what they do, you do not end up suffering?</strong></p>
<p>I think so if you're semi-enlightened.</p>
<p>You suggested already that you can have children without their causing your suffering.</p>
<p>If I know children, they'll transgress in various ways, large or small -- and you're probably supposed to interact with them and correct their behaviour -- maybe without stopping-loving them though.</p>
<p>There's some <a href="https://buddhism.stackexchange.com/a/7760/254">doctrine here</a> about choosing a spouse or partner, for what that's worth -- preferably one who is equal.</p>
<p>I think that a or the key to &quot;not suffering&quot; is to behave ethically. There's a sutta <a href="https://www.accesstoinsight.org/tipitaka/an/an11/an11.001.than.html" rel="nofollow noreferrer">Kimattha Sutta: What is the Purpose? (AN 11.1)</a> which begins ...</p>
<blockquote>
<p>I have heard that on one occasion the Blessed One was staying near Savatthi in Jeta's Grove, Anathapindika's monastery. Then Ven. Ananda went to the Blessed One and on arrival, having bowed down to him, sat to one side. As he was sitting there he said to the Blessed One: &quot;What is the purpose of skillful virtues? What is their reward?&quot;</p>
<p>&quot;Skillful virtues have freedom from remorse as their purpose, Ananda, and freedom from remorse as their reward.&quot;</p>
<p>&quot;And what is the purpose of freedom from remorse? What is its reward?&quot;</p>
<p>&quot;Freedom from remorse has joy as its purpose, joy as its reward.&quot;</p>
<p>&quot;And what is the purpose of joy? What is its reward?&quot;</p>
<p>&quot;Joy has etc.</p>
</blockquote>
<p>I equate that &quot;freedom from remorse&quot; with non-suffering -- &quot;I do not regret it&quot;.</p>
<p>See for example <a href="http://www.buddha-vacana.org/formulae/anussati.html#anussati-4" rel="nofollow noreferrer">Sīlānussati</a></p>
<p>In context I think that an example of sīlānussati might be <a href="https://www.accesstoinsight.org/tipitaka/sn/sn07/sn07.002.than.html" rel="nofollow noreferrer">Akkosa Sutta: Insult (SN 7.2)</a> where the buddha seems to be happy.</p>
<p>In my experience that happiness might be in retrospect, i.e. good behaviour now leads to &quot;joy&quot; later.</p>
<p>See also <a href="https://buddhism.stackexchange.com/q/35349/254">What is the basis?</a></p>
