Sadly, I've never married........But if I had, I would have never cheated on my wife......no matter what.
If I had found out she screwed my best friend, I would have simply packed my bags and moved out.........no argument, no yelling and screaming, no nothing.
There also would have been no reconcilliation, and no marital counseling...........
As for my ex-best friend, win or lose, at least I would have gotten in the first punch and left him something to remember for the rest of his life...........
I think the child support payments is pain enough, not to mention if he was already in a relationship, he will have to deal with that.