So I’ve had this fwb for 6 months and 2 days ago she tells me she’s going to drink some beers with this dude at the park. We live in the same house at university and her bedroom is right next to mine. That day it is raining so they go for like 30 minutes and then they come back home. When I get back home I hear them both in her room and I’m a little uncomfortable about the situation. Time passes and they keep drinking in her room.

The outcome of all of this is I’m 100% sure they had sex, they spent 8+ hours in her room drunk, I heard lots of giggling, lights were off, heard music on and strange noises. Fucking sickening. They were both also very drunk. My action after this was leaving the house, I left around 10pm without telling her I was going. She messaged me asking me to call her and shit and I have just been ignoring her and not giving her answers.

Tonight I had an arrangement with some friends to have a party at that same house so we’ll be driving down there later on today. I’m wondering if I should hard next her as this will probably involve moving out of the house and staying with family. I know fwb aren’t meant to be loyal but she definitely crossed a line by overtly fucking this dude in the same house as me, whilst drunk, for hours on end. I am also wondering what kinda treatment I should give her when I see her tonight at the house, radio silence and pretend she’s dead? Answer her questions vaguely and say I don’t wanna talk? Part of me wants to insult her and call her a worthless slut etc. but that might just make her think that I’m butthurt