I cheated in my first relationship back in high school. I "confessed", then she cheated to get back at me, and then our relationship slowly withered and died. I vowed to myself then that I'd never cheat again, and I never have.

i haven't cheated and don't plan to

The only time I have cheated on anyone I was with was when I was younger. I was with another female who allowed a stranger into her home and had sex with him. I guess my childish mind decided it was okay for me to cheat on her because she did it to me. I slept with an ex/friend of mine at the time who was in a serious relationship. My girlfriend never found out, still doesn't know to this day and I think my ex/friend's girlfriend probably figured out. He wasn't very trust worthy and had cheated on his girlfriend many times before me.

I only regret it because the guy is a total jerk and I really, really dislike him. I don't regret the act of cheating.

Also, I have been the 'other woman' before but it was not my doing. I was with someone for a few months/sleeping with them already and whatnot before he admitted that he was married. (His wife was in another state currently because of travel issues, that's how I didn't know.)

It ended horribly for me because he ended up making her the 'other woman' to me. I basically used the last remaining days with him around having meaningless sex. I just kind of used him for sex until he was pulled back to whatever state he had fled from.