Men-What's the hardest thing about forgiving a women for cheating on you and her asking you to take her back?

What thoughts go through your mind that would make you say yes, then on the other hand say no? Does your mind start to wonder as far as what she did with this other person? I know when that happend to me, the hardest part of it all was the thoughts of what happened even though I tried to shake them, things would just pop into my head even if I wasn't thinking about it. The thought of another man with your lady, what happened, to me she's tainted and that was the hardest part of accepting her back, I coulnd't, I didn't. Please be honest, especially about the part that I had trouble with, those thoughts, I want to know if I stand alone on this or if other men felt the same as I did.