My friends wife is cheating on him. Different guys on business trips mostly. And she travels a lot. Knowing them both makes for a pretty difficult situation. If I tell him and she finds out I'm toast because I would not put it past her to seek a hefty payback. Anonymous won't work either because she confessed a lot to me one night and I imagine the snitch list pretty short. Most of the guys are married so I run an equal risk of getting the snot beat out of me if I name any names. Still I really feel for the guy because no one deserves a high-health-risk liar for a wife. So I'm stuck looking for a way to tip him off without having him immediately confront the situation (and potentially I get outted). Advice?

I deleted the original question and revised it a little.