Infidelity: Forgive and forget??

I have an open relationship in terms of communication. I'd want him to come to me before he decided to bang someone else (threesome? sure! Bang that guy? Make sure he's clean! etc.) So if he was unfaithful, nope, I'm gone.

Never gave them a second chance of doing it again. I've been cheated on twice. I ended the relationship both times.

I've had few past loves cheat on me. The relationships didn't last long afterwards. I ended up not ever trusting them and would break off the relationship.

I've been cheated on once and it was hard to forgive the person. I wanted to forgive and forget but the only thing that came to my mind every time I looked at him was a vision of him and the other person. Our relationship ultimately ended due to the fact that the trust I had for him was destroyed.