Should I believe her

Why bother?

She is cheating on you anyway in other ways.

At this point it is about should I try to rebuild trust or move on. I basically have to believe something that is unbelievable in order to trust her again.

If my wife kissed and lay in bed with another man, that would it for me. Whether or not she had sex with him is irrelevant. She cheated.

If you want to try to save the marriage, you should go to couples therapy. Frankly, she owes it to you to work to fix your marriage, hopefully she accepts responsibility for what she did (if not, then any reconciliation is impossible).

I am pretty sure I would just end the marriage if this happened to me.

Only you can answer that question and I suspect you already have. Go back and read the other posts you've made on A2K, I think you'll find the answer.

She stopped communicating with him immediately, is willing to work on it, we are going to counseling. I do love her. Just FYI, I do not blame myself but I was not the best husband. Veteran with PTSD so I lack empathy and the only emotion I show is anger. Never harmed her or put a hand on her in anger, but not treating her well is the only reason I might be willing to give her a 2nd chance.

Well do that then, seek couples counselling. Once things are out in the open and you're talking about them they don't fester.

But nobody has answered my question. Very unbelievable...is it possible?