Like China Doll put it so well, pride and self respect. I also have a strong concience and would never cheat/lie/hurt anyone else intentionally and act like it was nothing the next day. Maybe it makes me naive but I've seen too many people like that and I've made sure they've stayed out of my life for good. I live life by my own morals and nothing in life would ever make me act against them. Its my conscience again, but I think I'm lucky to have it (clearly not a lot of people do) coz I have no regrets or guilt about my past and hopefully never will.