GAB Session: When did you realize it was time to get rid of a liar, a cheater, or a jerk?

Ever dated someone who was dishonest, unfaithful, or thoughtless?
The premise of "Dating a Liar, a Cheater, and a Jerk: 100 Reasons Why You 'Should' Take Him Back" is there are NO reasons to give him a second chance.
So when did you realize it was time to get RID of a liar, a cheater, or a jerk?
Tell us your story!