How to Tell if Your Spouse Is Lying
To tell if your spouse is lying to you, look for physical behaviors that indicate they aren't being honest. Watch them for excessive blinking when you start talking to them about an uncomfortable topic, as this can indicate that they're lying. You can also look for fidgeting, as this is another telltale sign. For example, your spouse might start shifting their feet, touching their face, or rubbing an object repetitively. Another common sign of lying is noticeable swallowing or gulping due to excessive saliva.
Look for excessive blinking. This may occur when you start talking to him about an uncomfortable topic. If you are talking to your spouse about something he is lying about, he may start to panic. Occasionally the lying spouse may actually slow down his blink rate going into the lie and speed it up afterwards. Blinking frequently can be a reflex in this case. For example, you might ask your spouse, “Did you send the plane ticket to my mother for the holidays?” Perhaps he is lying about having a good relationship with your mother and didn't send the ticket. So an increase in blinking during the conversation may occur. Make eye contact. If your spouse avoids or overly tries to make eye contact then she may be lying about your current topic of discussion. A liar may avoid eye contact, but she may also try to overcompensate for lying by establishing eye contact for too long. Use the eye contact behavior as a gauge in conjunction with the other behaviors. You may ask your spouse, “Did you lose my high school trophy?” She could lie and say no while avoiding your gaze, but also stare you down while denying it. See if your spouse is scratching excessively. A sudden increase in scratching by your spouse during a conversation can indicate lying. This is sometimes an indication of heightened nervousness. The scratching may occur anywhere on the body. For example, you may ask your spouse “Are you going out drinking again?” He may scratch his head and deny this. Watch your spouse for fidgeting. This is a common indicator of lying. Your spouse may fidget in place, shift her feet, touch her face, or rub objects around her. She may also become suddenly very still. For example you may ask her, “Did you go to the casino with your paycheck again?” And she may shift in their seat while denying it. Another example may be you asking your spouse, “Do you want to meet me for dinner tonight?” And she agrees, but doesn't mean it—meanwhile she is fondling some jewelry on her person while answering you. If your spouse is concentrating on her lie, this takes more energy and focus than telling the truth, which may cause movement to cease or be suppressed. Glance at your spouse's swallowing behavior. If your spouse is swallowing in gulps or drinking a lot he may be lying. Changes in saliva production can be a biological response to lying. The saliva change can be an over-production which will result in excessive swallowing or gulping. The change can be an under-production, which would result in more drinking. An example might be you asking your spouse “So, another late night at work with the new boss?” He may swallow hard when denying it or take a sudden drink of water. Watch for combinations of these signs. One of these behaviors alone does not mean your spouse is lying. Just because she takes a sip of water when you ask her a hard question, you cannot assume she's being dishonest — she may truly be thirsty. Instead, watch for clusters of these signs. If she is fidgeting and avoiding eye contact, and you pick up some verbal cues as well, that is a better indication of dishonesty than only one of the behaviors. Catch the inconsistencies. This is the most basic verbal method for telling if your spouse is lying. Try to use logic. If a person hears an unexpected loud noise, then he will look towards it. So if he says they ran away without looking at all—he is probably lying. This can be difficult if you don't have all of the information regarding the situation your spouse may be describing. For example if you ask your spouse “Did you come straight home from dropping the kids off at school?” He might say he did. Later you notice the car's odometer is reading double the mileage it should for the day without it having been used again. That would be an inconsistency. A more verbal inconsistency might be you asking your spouse “Did you buy tickets to the concert today?” The spouse may say yes, but you knew couldn't have because the news said it was already sold out. Ask an unexpected question. Another name for this is “tripping them up.” This is more useful if you suspect your spouse has told several lies. You want to catch her by asking her something that is now impossible or embarrassing because of her dishonesty. One example of this might be for a spouse that has repeatedly hidden bad financial investments from you and lied about it. You could try asking her, “Let's go to the bank and ask the agent to provide us all the tax forms.” Another example could be for a spouse that is habitually lying about hanging out with friends late at night so you tell her “I've gotten us two tickets to the theatre tonight.” Ask for details. Notice if you get too much detail or rambling from your spouse. If your spouse is in an uncomfortable situation, or one he feels guilty about, he may have over-thought how he will get out of it. A lying spouse may ramble on and on about what he was doing, where he was, and who he was with if he put a lot of care into the lie to cover his tracks. An example might be you asking your spouse why he is three hours late to your dinner date and he answers something such as, “I was driving in rush-hour traffic, there was an elderly lady crossing the street, an ambulance had to get by, construction blocked the road, and it was down to one lane on the bridge…” Listen for unease. This can manifest as hesitation in the voice. This may be a sign of anxiety from your spouse for lying. If there are a lot of pauses in the speech patterns of your spouse then this can be an indicator of lying. An example of this could be you asking your spouse about where she has been all day and she lies with an answer such as, “Oh, I…um… have been…. Um… with my friend Jane.” Lots of pauses in speech or stumbling may suggest lying because it takes more mental energy to maintain and tell a lie than simply tell the truth. This is especially true if the person is asked a more complex question — she will need time to formulate an answer that is consistent with her story. Talk to a witness. One way to catch your spouse in a lie is to find someone else to contradict his version of events. You need to be careful with this method as the witness is also capable of lying or being inaccurate. It may be helpful to talk to multiple witnesses to get more consistency in an answer. If you ask only one co-worker then she may say your spouse was there—but could be covering for him. However, if two or more co-workers all say your spouse was there, then this is most likely true. For example you may ask your spouse if he was at work during business hours like he claimed to be. Then you can ask witnesses, in this case co-workers, if your spouse was telling the truth. But if two or more witnesses claim your spouse was lying then you know with more certainty this is the case. 
Look for excessive blinking. Make eye contact. See if your spouse is scratching excessively. Watch your spouse for fidgeting. Glance at your spouse's swallowing behavior. Watch for combinations of these signs. Catch the inconsistencies. Ask an unexpected question. Ask for details. Listen for unease. Talk to a witness. 