I recently found myself in a very uncomfortable position. I found out (with my own eyes) that one of my good friends who is married to another friend of mine is cheating. Obviously it is not my place to pass judgement or tell on them but it still makes me feel weird.
From what I can gather, they are meant to be exclusive to each other but perhaps privately they have an agreement, perhaps they are allowed to fool around but not tell, perhaps their sex lives are at a point where they do not turn each other on anymore. Who knows, relationships take on so many different forms now-a-days.
Anyway, just thought I'd share. I'm sure all those reading this post have been in a similar position.