I recently found out my ex boyfriend dated another girl at the same time he was dating me and he hit on all my friends. I became friends with the girl he cheated on. He completely fooled me with the nice guy facade. What should I do? I'm extremely angry and I'm considering revenge but some say two wrongs don't make a right. But at the same time, I want him to learn his lesson and stop hurting other girls for good. What should I do?