Should I spread the word?
I just found out recently from a co-worker that last year, my sister-in-law had a very short-term affair with a guy I work with, and her husband has no idea about that. The problem is that her husband is one of my best buddies, and if he ever learns that I knew and I didn't tell him, he would be really mad. I want to believe that she is not a **, but something tells me that she is easier that the regular married woman and sometimes she has eyes for other guys too. They have been married for 6 years and have no kids. Should I warn him? Or should I keep it for myself only? By now I didn't even tell my wife (her sister).
Don't tell him. Back away. If she's a ** let her dig her own grave. They'll both end up hating you if you get in the middle of that.