Search Results: should we break up girlfriend

I get very bad vibes from my brother's girlfriend. Whenever she sees me, she makes faces like as if she hates me or something for no reason. Another thing I noticed is that he hates her mother because she says that her mother who is a housewife steals money from her husband. And recently her mother is teaching her how to drive. That's so weird. She acts all dumb too when she is with my bro. And many scenarios like she sees me like something low - see thinks I work in back office despite she seeing my LinkedIn. And she knows problems in our family like my mom is paralyzed due to brain stroke and dad ( they both have high blood pressure) , I have work from home , so bro has to help at home - still she forces my brother and argues with him for overnight stay (2 days) and all. She behaves very incentive. All the time, I only see my bro explaining her and begging her to understand and she still argues and finally after 2-4 days argument from getting tired of explaining her, my bro stops explaining her and then finally she agrees.

I have already met my soulmate who i can never be together with and we aren't in contact anymore. He helped me and i helped him and our roles in each other's lives are over. So i don't have to worry about "the one"
The biggest deal breaker in a relationship for me is cheating and i have always advised a break up if your SO cheats. Cheating is the same reason why i am scared to be in a relationship too. It seems that many people here and irl supports cheating too. I had a guy tell me he will pour sulphuric acid on to my face because i asked a girl to break up with her cheating boyfriend. I know a female user here who everyone compliments on how she's such a submissive good girlfriend while she's flirting and sexting her guy friend. Even some of my friends in committed relations talk about new crushes and flirting with hot losers.(They say it's for fun)
Whenever i express my hatred towards cheating, people ask "Did you get cheated on or something?". Obviously i did not. But i feel like what they're saying is i don't have the right to be upset about cheating.
Anyway i got a player guy who have always wanted to "date" me since i am not easy and i am 99.9% sure he will cheat. So if i date him and when he cheats, i may finally be able to get rid of my fear. Once i become immune, i believe that i won't be always thinking if my future SO (someone i love) is cheating and even if he is, I would be used to it.
You would feel like i am being a hypocrite rn so i will stop expressing my anger towards cheating and such questions from this moment onwards. And yes i am alright being a miserable girl who would probably be pitied on (Ik i need help🤷‍♀️).