03-07-2012, 03:46 AM
I wouldn't date someone with a history of cheating. It's pretty much already been said, but "once a cheater, always a cheater". I also think your friend would be VERY upset if you dated a guy who broke her heart in that kind of way.
In general, dating a friend's ex depends on the situation, and how bad their break up was. If you're questioning if it's a good idea, ask your friend.