I totally get it, I really do. But you're projecting your own good intentions and character on to a man who has none -- HE IS A PREDATOR.
And you're right -- you don't "correct the behavior" of two people caught up in an affair. The way it was explained to me is "you can't teach an adulterer," and I think that's true.
I do respect your stand; I've just never seen where it's been effective, and a lot of times it's actually harmful (for the reasons I stated).