I imagine this post is going to seem weird to a lot of people, but I'm part of a very small but very close friendship group, there's me (M), my housemate (V) , and a girl we've known for years (A). 

A is over our house almost everyday, and for the last few months A and V have been getting worryingly close; they'll cuddle into each other on the sofa, playfight, flirt etc. It's very difficult for me to watch, because these guys are my best friends, and V has a girlfriend, who is totally infatuated with him. She's also a very very lovely girl who absolutely does not deserve to have her first boyfriend do this to her.

There's far more going on, and I know far more than they think I do; I know that V's explicitly told A that he wants to fuck her at least once, and I know nudes have been exchanged. A knows I know, V does not. Other far weirder things have happened too, but I won't get into that.

With all of this in mind, when A came over again the other day I called them out. I told them to think of V's girlfriend above anybody else. I confronted A about it and told her that it makes me uncomfortable, and they haven't done it since.

V's girlfriend has no idea, of course. She has every right to know, but I'm just not prepared to go behind both my best friends' backs like that, especially since V's gf and I aren't close at all. 

Both V &amp; A have severe depression too, and A's told me that the guilt of this situation coming out will be enough to tip V over the edge and make him kill himself; I don't know if she's bluffing or not, but I really don't want to take the chance. 



