user9846: Of course, after getting enlightened, One is free from worry: now the person is in higher dimension and is always happy, as he knows how perfect everything is.
But still Buddha's family was there; I mean, wasn't his family his responsibility?
I remember when the Buddha came back to the palace and met his wife: she asked, "just tell me, if it was possible to get enlightenment in the palace."
How necessary is it to leave our families to practice, and if it is not necessary why didn't Buddha just come back? I always feel sad when I think about Siddhārtha Gautama's wife Yashodhara.
If one is enlightened, he can not hurt anyone feelings: but Buddha hurt Yashodhara's feelings?
I know I am incorrect somewhere, because after all He was enlightened, so he can not take wrong decision.

user254: Why Buddha was not worried about his family after enlightenment?
There's a section titled "Celibacy versus Responsibility" towards the end of this article, A Happy Married Life.
Here are some excerpts:

His sacrifice is considered all the more noble because he set aside his personal needs and desires in order to serve all of mankind for all time.
Had he remained in the royal palace, his service would have been confined to only his own family or his kingdom.
One of the Buddha's earliest tasks after gaining his Enlightenment was to return to his palace to enlighten the members of his family. In fact, when his young son, Rahula asked the Buddha for his inheritance, the Buddha said that Rahula was heir to the richest wealth, the treasure of the Dhamma. In this way, the Buddha served his family, and he paved the way for their salvation, peace and happiness.
Another important fact was that the Buddha knew that his wife and son would not starve in his absence. During the time of the Buddha it was considered quite normal and honorable for a young man to retire from the life of a householder. Other members of the family would willingly look after his dependents. When he gained his enlightenment, he was able to give them something no other father could give — the freedom from slavery to attachment.

In summary:

He did it for everyone, not only his family
The members of his family, too, were subject to illness, old age, and death. If he had continued his life as a prince or worldly ruler, he would not have found how to liberate them from that.

How necessary is it to leave our families to practice
Is it hard to generalize? It's a choice, isn't it? A choice which has consequences. It's not "necessary", for example you don't have to be good and kind ... but intentional action has consequences.
And in some countries, I've read that most men do both, i.e. they leave their families temporarily (to live as monks) and (after disrobing) return to live with their families.
Buddhism doesn't seem to me to be anti-marriage. If I remember correctly, some of the rules in the Vinaya are motivated towards not breaking up families.
Look at the introduction though:

"If a man can find a suitable and understanding wife and a woman can find a suitable and understanding husband, both are fortunate indeed."

It may be that practice is necessary in order to be suitable and understanding.
Also everyone must "leave their families" eventually (i.e. people die).
If one is enlightened, he can not hurt anyone feelings
If one is not enlightened, then I think that one may tend to be ruled by feelings: your own feelings, your wife's feelings, your mother's feelings, your children's and friends' and so on.

user8157: 
But still Buddha's family was there; I mean, wasn't his family his
  responsibility?

In the Buddha's time families lived in clans or extended families. The Buddha's family was very wealthy and Yashodhara was fully provided for. 
Also, it is highly probable Gotama rarely (if ever) had sex with Yashodhara because the suttas seem to depict Gotama as childless & having lost interest in sensuality (AN 3.39; MN 75) while he lived in his three palaces. 
While rarely hypothesized in Buddhism, it is highly likely, after 12 years of childless marriage, Gotama had sex with Yashodhara to have a son at the request of his father. This is because as soon as Gotama had a son, he left home. 
Contrary to the legends that say Gotama left home secretly, the suttas (e.g. MN 26) state Gotama left home seeing the tears of his parents stream down their face. Therefore, it seems Gotama possibly made a deal with his family, if he bore an heir to the throne, he could leave home. 

I remember when the Buddha came back to the palace and met his wife: she asked, "just tell me, if it was possible to get enlightenment in
  the palace."

That the Buddha returned home showed he cared about his family. The Buddha's son became an arahant and supposedly also Yashodhara, who is mentioned in the suttas with another name. Therefore, the Buddha gave them the greatest gift.  

How necessary is it to leave our families to practice, and if it is not necessary why didn't Buddha just come back? I always feel sad when
  I think about Siddhārtha Gautama's wife Yashodhara.

It is not necessary to leave your family permanently but if you want to practise very deeply you might have to leave them for many months and give up sex for a time. 

If one is enlightened, he can not hurt anyone feelings: but Buddha hurt Yashodhara's feelings?

Yashodhara's feelings were her own kamma. The Buddha did not hurt her. If she was hurt, she hurt herself. 
In the Buddha's time, I imagine women busied themselves with children & performing activities with other women. I imagine is was not the same as today, where husbands & wives live in what is called a 'nuclear family'.

I know I am incorrect somewhere, because after all He was enlightened, so he can not take wrong decision.

When Gotama left home, he was not enlightened. However, fortunately, his leaving home ended being the right decision since he provided salvation to many people. 

user738: 
But still Buddha's family was there; I mean, wasn't his family his responsibility?

Yes.

I remember when the Buddha came back to the palace and met his wife: she asked, "just tell me, if it was possible to get enlightenment in the palace."

You remember? 

How necessary is it to leave our families to practice, and if it is not necessary why didn't Buddha just come back? I always feel sad when I think about Siddhārtha Gautama's wife Yashodhara.

Gautama had this urge to find out the meaning of this life and suffering, and that was his ONLY goal. He wanted to leave so he could concentrate on that. I am going to quote Chuck Palahniuk here -If you want to make an omelette, you have to break some eggs. This is the SAME with any other goal. You have to make some sacrifices.

If one is enlightened, he can not hurt anyone feelings: but Buddha hurt Yashodhara's feelings?

Cannot hurt any feelings? That doesn't make any sense. Feelings are for the person who is at the receiving end. Not for the Buddha. Have you heard of the saying "truth is bitter"? Bitter is a feeling that we experience because of our subjective minds. 

I know I am incorrect somewhere, because after all He was enlightened, so he can not take wrong decision.

What's your point? There is NO SUCH THING as right decision and wrong decision. It purely depends on the context of the situation. If Gautama wants the answer he is seeking, then he has to leave the family. Period. It is NOT WRONG. He did it because he was yearning for it. It cannot happen to you or me, because we don't have the guts to sacrifice and drop everything that doesn't matter and go towards our goal. If Gautama wanted to rule the world or a kingdom, he would have taken different actions. Actions are according to the goal and the situation. Don't think in terms of marriage/divorce law or morality here.  
I also want to add finally that, to go for Nirvana is definitely a selfish matter. If I want to find out what it is, it is because it is MY DESIRE to find out. Without Desire, you cannot live, breathe, feel or do anything. It is a desire to find out about life that Gautama went forth with. And whether you like it or not, it is selfish. And why not be selfish about this? Yes you will hurt some feelings, but like I said, you cannot have everything, you have to sacrifice.

9846: <p>Of course, after getting enlightened, One is free from worry: now the person is in higher dimension and is always happy, as he knows how perfect everything is.</p>

<p>But still Buddha's family was there; I mean, wasn't his family his responsibility?</p>

<p>I remember when the Buddha came back to the palace and met his wife: she asked, "just tell me, if it was possible to get enlightenment in the palace."</p>

<p>How necessary is it to leave our families to practice, and if it is not necessary why didn't Buddha just come back? I always feel sad when I think about Siddhārtha Gautama's wife Yashodhara.</p>

<p>If one is enlightened, he can not hurt anyone feelings: but Buddha hurt Yashodhara's feelings?</p>

<p>I know I am incorrect somewhere, because after all He was enlightened, so he can not take wrong decision.</p>
 254: <p><strong>Why Buddha was not worried about his family after enlightenment?</strong></p>
<p>There's a section titled &quot;Celibacy versus Responsibility&quot; towards the end of this article, <a href="http://www.accesstoinsight.org/lib/authors/dhammananda/marriage.html" rel="nofollow noreferrer">A Happy Married Life</a>.</p>
<p>Here are some excerpts:</p>
<blockquote>
<p>His sacrifice is considered all the more noble because he set aside his personal needs and desires in order to serve all of mankind for all time.</p>
<p>Had he remained in the royal palace, his service would have been confined to only his own family or his kingdom.</p>
<p>One of the Buddha's earliest tasks after gaining his Enlightenment was to return to his palace to enlighten the members of his family. In fact, when his young son, Rahula asked the Buddha for his inheritance, the Buddha said that Rahula was heir to the richest wealth, the treasure of the Dhamma. In this way, the Buddha served his family, and he paved the way for their salvation, peace and happiness.</p>
<p>Another important fact was that the Buddha knew that his wife and son would not starve in his absence. During the time of the Buddha it was considered quite normal and honorable for a young man to retire from the life of a householder. Other members of the family would willingly look after his dependents. When he gained his enlightenment, he was able to give them something no other father could give — the freedom from slavery to attachment.</p>
</blockquote>
<p>In summary:</p>
<ul>
<li>He did it for everyone, not only his family</li>
<li>The members of his family, too, were subject to <a href="https://en.wikipedia.org/wiki/Four_sights" rel="nofollow noreferrer">illness, old age, and death</a>. If he had continued his life as a prince or worldly ruler, he would not have found how to liberate them from that.</li>
</ul>
<p><strong>How necessary is it to leave our families to practice</strong></p>
<p>Is it hard to generalize? It's a choice, isn't it? A choice which has consequences. It's not &quot;necessary&quot;, for example you don't have to be good and kind ... but intentional action has consequences.</p>
<p>And in some countries, I've read that most men do both, i.e. they leave their families temporarily (to live as monks) and (after disrobing) return to live with their families.</p>
<p>Buddhism doesn't seem to me to be anti-marriage. If I remember correctly, some of the rules in the Vinaya are motivated towards not breaking up families.</p>
<p>Look at the introduction though:</p>
<blockquote>
<p>&quot;If a man can find a suitable and understanding wife and a woman can find a suitable and understanding husband, both are fortunate indeed.&quot;</p>
</blockquote>
<p>It may be that practice is necessary in order to be suitable and understanding.</p>
<p>Also everyone must &quot;leave their families&quot; eventually (i.e. people die).</p>
<p><strong>If one is enlightened, he can not hurt anyone feelings</strong></p>
<p>If one is not enlightened, then I think that one may tend to be ruled by feelings: your own feelings, your wife's feelings, your mother's feelings, your children's and friends' and so on.</p>
 8157: <blockquote>
  <p><em>But still Buddha's family was there; I mean, wasn't his family his
  responsibility?</em></p>
</blockquote>

<p>In the Buddha's time families lived in clans or extended families. The Buddha's family was very wealthy and Yashodhara was fully provided for. </p>

<p>Also, it is highly probable Gotama rarely (if ever) had sex with Yashodhara because the suttas seem to depict Gotama as childless &amp; having lost interest in sensuality (<a href="https://suttacentral.net/en/an3.39" rel="nofollow noreferrer">AN 3.39</a>; <a href="https://suttacentral.net/en/mn75" rel="nofollow noreferrer">MN 75</a>) while he lived in his three palaces. </p>

<p>While rarely hypothesized in Buddhism, it is highly likely, after 12 years of childless marriage, Gotama had sex with Yashodhara to have a son at the request of his father. This is because as soon as Gotama had a son, he left home. </p>

<p>Contrary to the legends that say Gotama left home secretly, the suttas (e.g. <a href="https://suttacentral.net/en/mn26" rel="nofollow noreferrer">MN 26</a>) state Gotama left home seeing the tears of his parents stream down their face. Therefore, it seems Gotama possibly made a deal with his family, if he bore an heir to the throne, he could leave home. </p>

<blockquote>
  <p><em>I remember when the Buddha came back to the palace and met his wife: she asked, "just tell me, if it was possible to get enlightenment in
  the palace."</em></p>
</blockquote>

<p>That the Buddha returned home showed he cared about his family. The Buddha's son became an arahant and supposedly also Yashodhara, who is mentioned in the suttas with another name. Therefore, the Buddha gave them the greatest gift.  </p>

<blockquote>
  <p><em>How necessary is it to leave our families to practice, and if it is not necessary why didn't Buddha just come back? I always feel sad when
  I think about Siddhārtha Gautama's wife Yashodhara.</em></p>
</blockquote>

<p>It is not necessary to leave your family permanently but if you want to practise very deeply you might have to leave them for many months and give up sex for a time. </p>

<blockquote>
  <p><em>If one is enlightened, he can not hurt anyone feelings: but Buddha hurt Yashodhara's feelings?</em></p>
</blockquote>

<p>Yashodhara's feelings were her own kamma. The Buddha did not hurt her. If she was hurt, she hurt herself. </p>

<p>In the Buddha's time, I imagine women busied themselves with children &amp; performing activities with other women. I imagine is was not the same as today, where husbands &amp; wives live in what is called a 'nuclear family'.</p>

<blockquote>
  <p><em>I know I am incorrect somewhere, because after all He was enlightened, so he can not take wrong decision.</em></p>
</blockquote>

<p>When Gotama left home, he was not enlightened. However, fortunately, his leaving home ended being the right decision since he provided salvation to many people. </p>
 738: <blockquote>
  <p>But still Buddha's family was there; I mean, wasn't his family his responsibility?</p>
</blockquote>

<p>Yes.</p>

<blockquote>
  <p>I remember when the Buddha came back to the palace and met his wife: she asked, "just tell me, if it was possible to get enlightenment in the palace."</p>
</blockquote>

<p>You remember? </p>

<blockquote>
  <p>How necessary is it to leave our families to practice, and if it is not necessary why didn't Buddha just come back? I always feel sad when I think about Siddhārtha Gautama's wife Yashodhara.</p>
</blockquote>

<p>Gautama had this urge to find out the meaning of this life and suffering, and that was his ONLY goal. He wanted to leave so he could concentrate on that. I am going to quote Chuck Palahniuk here -<code>If you want to make an omelette, you have to break some eggs.</code> This is the SAME with any other goal. You have to make some sacrifices.</p>

<blockquote>
  <p>If one is enlightened, he can not hurt anyone feelings: but Buddha hurt Yashodhara's feelings?</p>
</blockquote>

<p>Cannot hurt any feelings? That doesn't make any sense. Feelings are for the person who is at the receiving end. Not for the Buddha. Have you heard of the saying "truth is bitter"? Bitter is a feeling that we experience because of our subjective minds. </p>

<blockquote>
  <p>I know I am incorrect somewhere, because after all He was enlightened, so he can not take wrong decision.</p>
</blockquote>

<p>What's your point? There is NO SUCH THING as right decision and wrong decision. It purely depends on the context of the situation. If Gautama wants the answer he is seeking, then he has to leave the family. Period. It is NOT WRONG. He did it because he was yearning for it. It cannot happen to you or me, because we don't have the guts to sacrifice and drop everything that doesn't matter and go towards our goal. If Gautama wanted to rule the world or a kingdom, he would have taken different actions. Actions are according to the goal and the situation. Don't think in terms of marriage/divorce law or morality here.  </p>

<p>I also want to add finally that, to go for Nirvana is <strong>definitely a selfish matter</strong>. If I want to find out what it is, it is because it is MY DESIRE to find out. Without Desire, you cannot live, breathe, feel or do anything. It is a desire to find out about life that Gautama went forth with. And whether you like it or not, it is <strong>selfish</strong>. And why not be selfish about this? Yes you will hurt some feelings, but like I said, you cannot have everything, you have to sacrifice.</p>
