I would get pissed at the friend for not being honest. If they aren't being honest to their partner, how do I know they're honest with me? Unless their partner was a total _____ and deserved it.

For the undeserving partner, I'd make it a point to be there for them more than usual.

I would mind my own business. I make it a rule not to get into the affairs of others. As much as you may think you are doing the right thing, sometimes the messenger is the one that gets shot.

I definitely would want to tell them, but I don't know if I would. If I tell them, they'll be angry that I did and if I don't tell them and they found out that I had known then they'd be angry that I didn't say something. My best friend I would probably tell, because we've already been through a lot together and she knows that I'm just looking out for her.

If it was my friend, there's no way I would threaten them or go behind their back and tell their partner. While cheating is not ok, it is usually a symptom of deeper relationship issues, and unless advice was asked for, I wouldn't pass judgement without being one of the people in the relationship. My best friend, whose marriage had always been awful, had an affair years ago and ended up leaving her husband for the man she fell in love with and they're very happy to this day. I'm not saying the way she went about things was morally acceptable, but she had her reasons for the decisions she made and the way she went about things, and it was her life, not mine, to call the shots on.

If it was my friend being cheated on, however, I would tell them.

i would share my opinion with them even though they probably wouldn't like it but i wouldn't get involved otherwise.

If I found out my friend was having an affair I would ask definitely ask them about it, but there is absolutely no way I would tell their spouse. I wouldn't bring up so I could pass judgment on them or tell them how horrible they are for having an affair, but I would want to know if there was a serious problem or if they needed someone to talk to. In this situation my friend would be my top priority and there is no way I would jeopardize our relationship to tell their spouse, especially when I don't know the whole story.

I'd actually make it a point to avoid the spouse because it would just be too awkward.

I'd keep my mouth shut. Probably get mad at my friend, but ultimately he/she is your friend, not their spouse.

Interesting so...it seems people would protect the friend but if the friend were the one being cheated on they would pop the cheater. Very, very interesting!

I would definitely have a conversation with my friend to find out how deep the affair goes and how they're feeling about both relationships. Then I would try and give them advice if possible, either to break off their affair or to consider ending things with their current 'partner'. I would tell them that I do not support their decision to cheat but it is their own decision and they need to make their own choice about what's best for them. And then I'd do my best to be there for both parties when everything comes crashing down around them.

I'd definitely want to talk to them about it, but I don't think I'd tell their spouse or significant other.

Stay out of it! It is not my relationship therefore is not my business. You never know what can blow up in your face. I find it best to just let things be and allow that partner to find out for them self.

I admit it, I'm tactless and have this thing about me where i feel i have to be the goody-goody. If there's cheating, I usually do say something. I know I shouldn't, but I can't stand my friends doing stupid shit, or having shit done to them. A friend will tell you what you're doing wrong or what wrong is being done to them, despite the fact hell could break loose. It shows you care. And if I lose said friend after the whole thing, then perhaps they weren't much a friend to begin with.

I would talk to my friend after I found out and see what was going on from her point of view, and let her know how I felt about it. After that I would stay the hell away and pray she took my advice. The messenger always gets the blame and fall out.