From 9 Signs of a Cheater. So I never forget.

7. He's Being Caught in Lies About Other Things

If you catch him in a lie, your trust will naturally be damaged. Don't hold a grudge -- forgiveness is a good thing. You can forgive, but don't forget. If he consistently breaches your trust, it's establishing a pattern of behavior that leads to cheating. Do yourself a favor: If he keeps lying, whether these lies are big or small, get out while you can and don't let him talk his way back in.