During the night I had noticed some female stuff around (like make up in the bathroom, shoes in lounge room) and when I asked about it, he told me that he had a roommate and that she was getting on his nerves a fair bit and it didn't look good.
Anyway I shrugged that off, thinking nothing of it and the rest of the night went great; half a bottle of whiskey later we end up in his bed having sex.
The morning after, my suspicions came back fourfold, female items in his room that I missed the night before (lights were off the whole time), and he seemed to be in a bit of a hurry to get me out of the house. I shrugged it off again, cause we were mates and he couldn't have lied to me, right? So I ate breakfast gathered my stuff and as he walked me to my car he said, 'By the way, I have a girlfriend.' Then he shrugged - 'But it takes two to tango,so...'. I was speechless! I didn't say anything for a while, just left while I processed what just happened. Got angry and basically told him to go f*** himself.
I don't want anything to do with him and I just feel so stupid that I didn't listen to my instincts! I feel awful and sick to my stomach. I don't know what to do, I've never been in this situation before and I definitely don't make a habit of having casual sex!
I'm worried that if I tell his girlfriend, she won't believe me and it'll open a whole can of worms. By the same token, I feel like I should because I don't want him to get away Scott free either and I'm sure whoever she is, she deserves better than this!
Most Helpful Guy
There's no point in telling her. It'll only get you into stress and bother. Besides, you don't know her. Maybe she's not a nice person either.
If she was also your friend (or a relative), then I'd tell her. But, since she's not, don't bother. Snub your guy friend. That will be enough punishment for him.1