How do you catch your boyfriend in a lie?

Why bother trying to catch him in a lie! People don't lie unless they are covering something up. Beware! You have to be sure first he is lying. If he is a compulsive liar I wouldn't waste another day with this guy. Evidence is the key. Sometimes the only way for him to be truthful about these things is for you both to have a mediator; someone between you where he might feel that you're not going to go mental if he drops a bomb on you. Possibly go and see a councellor together?

If he can't be honest with you...what CAN he be for you?