A book by a founder of this site.
What is the Best Way to Discover the Truth?
How can you tell if a husband or wife, boyfriend or girlfriend is lying?
Unfortunately, it is very difficult to catch a lover lying by paying attention to his or her nonverbal behavior (body language) or by asking a lot of questions.
There are, however, several things you can do to encourage a spouse or romantic partner to be more honest with you in the first place. Typically, it is easier to get others to be more truthful than it is to catch them lying (see get others to be honest).
But, if you suspect that your spouse might already be lying to you, there are several very effective methods for discovering the truth.
In fact, these days there are so many different options for discovering deception that it is easy to find one that fits the nature of the problem at hand.