You know, if I were in a relationship I doubt I'd cheat on them. If it came to that, that means I'm over them anyway, and I don't get over people easily.
I never cheated on someone, and never will - I don't know how I would live with myself knowing that I'm not a faithful partner.
I've been cheated on once, but it was a really random relationship and nothing worked and I really had no feelings for them.. it was one of those kind of relationships where I dated them just so I can say I had someone.