In my case, I don't know for sure that anything happened between my wife and the OM when he came to visit; until she tells me for sure, it's easier to assume that something did without knowing any details, and forgive her for that in my heart.
I am TOTALLY fine with the "just-assume-they've-been-unfaithful" approach. In fact, it's what MWD teaches. It's the "I asked her if there was anyone else, and she said no, and I believe her" approach that just drives me BATTY.
