Appeal to him being respectful of your marriage, your wife and you.
I strongly disagree with this. If NOTHING is going on, you will look like a fool, and if SOMETHING is going on (and I believe it is) then you are asking a PREDATOR to be respectful and honorable.
Ain't gonna happen.
If he wants to confront someone, he should confront his WIFE. But only after he has hard proof. Puppy