Disclaimer: If you enter into a committed monogamous relationship, you owe it to your partner and yourself to remain that way. If the relationship goes sour and it's not worth saving, then move on. Open relationships or non-exclusive relationships are just that, open.
It happened to me twice; I got involved with a married man. I say it that way because I didn't know they were married when we first got involved and when I found out, I didn't move at lightning speed to end contact with them. I was pissed. They weren't honest with me like I was with them. One waited until things got hot and heavy and then decided they really liked me and should tell me the truth. After that experience, I've been on guard. So the second guy, I had to ask. He wasn't going to tell me. When I did ask, that scared him off. He didn't answer the question just walked away, literally. Two things he wanted to know as he was walking out the door were, was I going to kick him and if I was going to protest (meaning stop having sex with him). Looking back, I think he felt that was his only recourse in what he perceived to be a power struggle; end it with her before she ends it with me (this is my hindsight insight).
