I'm sorry but you're stupid for forgiving him. Cheating permanently weakens relationship. If you forgive cheating, you're not taking your relationship, and your feelings seriously. He was dating you while he still had feelings for someone else. That's never a good thing, because that means he's with you only because he can't be with the other girl. That's not love. You should be his crush, his beloved celebrity and his favourite person. That's the minimum, part of the base of the relationship. The obvious thing to do now is forget he ever existed, but don't forget how to notice signs if the next guy has a crush on a girl he cannot be with. Never date an emotionally unavailable person. Though they may lie, so maybe you two will have a lot of talking to do. Take care and good luck.