How do I forgive my ex-boyfriend?

You forgive him by sending the offense away from your mind. You don't dwell on past hurts. You realize that no one is perfect and that everyone has done things that they shouldn't have done and therefore you don't hold people up to a standard of perfection that you your self are not able to live up to. You realize that not forgiving a person only hurts you because your mind is replaying past hurts over and over again while the other person is out living their life and probably not even thinking of the things that you are allowing to bother you so much and rob you of enjoying each new day because your mind is still stuck in the past.