<human>: Can you give me the gist of the text in a nutshell?

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I spoke to my roommate and told him that his GF can't come over to our dorm everyday. I finally had my peace of mind until Thursday night when he brought her over. Luckily it was at 10 pm so it didn't matter as she was gone before 7 Am the following day. However, he just brought her back here as I am typing this. He told me he was going home "to stay" with family. 

I need some help putting the hammer down because I feel like I am living under someone elses rules instead of a shared living space. I don't want to change roommates but I can't handle his GF here every singleday!

Now I could try confronting him again but I feel like it would be pointless. I have two options that I can think of.
1) Straight up tell his parents or his GF parents that he keeps bringing his GF over here. This is a scumbag move but I shouldn't suffer when I'm paying 10 grand for housing. My money is more important than your GF.

2) Wait until the end of spring semester ends and finally say good riddance to that bitch.
<bot>: Roommate agreed to stop bringing his GF over but disregards agreement after a few days and I need help laying down the law.