If you truly loved him or still "love" him, forget about revenge; it's not a good thing if not a bloody evil! Try to avoid any communication (of whatever kind) with him, talk this out with your friends, go out and do some physical training, and I'm sure time will heal the wounds. Next time perhaps you should try to avoid getting yourself involved with someone who's still married...
Although I'm feeling for you because you're very sad now. but it seems that you're both at fault. Why did you get involved with a married man in the first place? If he's still married, don't you think you might have also hurt the feelings of his wife? Though he's unfaithful to his wife (the bloody idiot never deserves any love from anyone!), he is by no means owned by you or anyone else! And don't be possessive! I hate people talking about revenge! It is certainly unhealthy to you or anyone else! I hope my cold words will serve to make you feel better somehow. Just forget him and get on with your life, and I'm sure you'll find your true love one day.