Couple of things to clear up.
He's Catholic, and I just don't think divorce is an option, or it would have happened last summer.
First, once he was "caught", and I'm not entirely sure how that happened, he did everything to try to fix what was done. I believe it was a one time/ or short time thing last summer. He moved back into the house shortly before Christmas.
His daughters will hardly speak to him because they blame him for what happened, and his wife is all to willing to vilify him.
I would be absolutely blown over if she ever did anything outside of their marriage before his cheating, although, I'm totally blown away by this revelation. I beleive that her fling happened during the separation, but it was not just one night, according to my friend who witnessed her in the bar many nights.
As to tell him or not, I just don't think it is my place. He probably knows, and in my opinion, it would hurt more if I found out my friends knew too. We have a common friend, who he is closer to, but I know I'm not going to tell him either.
I'm just trying to see this from his perspective. I hate the fact that she is making him feel like such a low life, and acting so rightious. It just made me think what would I want from my friends, and I just don't know. With that, I'm going to just keep it to myself.