Basically I am a student a university in England who made the dumb decision to live with his girlfriend, who of course left him for another guy during the summer. I am in the process of trying to move out but the rental contract is in the way and I can't afford to pay rent on two rooms (currently sharing a house with five others). So basically I am stuck here for now. It's been like this for about a month so I basically ignored her. Recently she has started bring this guy over to stay and I hear them in the room next door talking,fucking etc. I see him around my house aswell. I tried being beta and talked to her about how it upset me and not to do it. She of course hamstered it saying "you just have to deal with it" and " I have been hurt before so you can too". I'm basically looking for advice either to stop him coming round or get my head right so it doesn't affect me. And yes I know I'm being a bitch.

TL;DR Forced to live with ex and new bf, how to deal with it.