this drives me crazy

My bfs roommates gf. She absolutely hates me for no apparent reason and has no issue voicing this to my bf. She once did it over text so I flipped and made sure he put her in her place. My bf sees no issue and still is polite to her and her bf. Ik he lives with them but he shouldn't be so friendly to someone he knows hates me. the girls bf is also mean but idk if that's cause his gf convinced him. She's two years older than me and doesn't have the best life situation but why does she have to be mean to me? How do I handle it. In person she tries to flirt with him like we were at the club and she wanted to keep hitting her butt into his but my bf was drunk and was looking at me and didn't notice. What should I have said?