Yes me.
I cheated only now ex husband very early on in the relationship. I had, what I now know was, an emotional affair that became physical once.
I regretted it immediately afterwards and pledged to myself that I'd never do it again - it said more about me as a person than it did about him or the relationship.
My current boyfriend cheated on his long term ex at the end of their relationship. I know the circumstances of the relationship and, whilst he shouldn't have done it, I can see how the situation led to it.
He owned up to it and the relationship ended. I didn't.
He and I would both now end a relationship before it got to that stage if we were unhappy. I trust him on that.
A lot of people cheat. A lot of men you date, who will tell you that they never have, will have done and just aren't being honest about it. I'd trust someone who was open and honest about their past over someone who pretended it was different.
However, I wouldn't forgive someone who cheated on me.