[PSY]

I've never been placed in your position before, but I've asked myself what I would do if I were faced with a similar situation. I believe I would talk to my friend first and essentially give him the opportunity to come clean, because I value my morals over any potential consequences to my friendships. After that, what you do depends on where your priorities are. I would be highly suspicious if my friend claimed they told their partner, and things carried on as usual (ex. they posted cute photos of each other on Facebook the next day). If that happened, I might even ask my friend what would happen if I followed up with their partner at that point, to see how my friend would react. I wouldn't want to be associated with someone who not only cheated on their partner, but also lied to me about telling their partner after the fact... so my value system would probably overrule my desire to avoid drama/getting involved on a deeper level.