Am I in the wrong

My girlfriend and I live apart and her family is super homophobic so I’m never allowed in the house (when they’re there) I recently quit working in my hometown and We used to see eachother everyday but now only once a week. She insist on hanging with our coworker who has mental issues (to be his friend) which I understand but I’ve caught him on multiple occasions starring at her ass and she says she never seen it cuz she’s turned around obvi. But I don’t trust this guy. He’s allowed in her house and they hang out late at night. I’m not comfortable with it and I feel like she doesn’t take that into consideration, she defends him with “he needs friends” but I need my girl, I fell left behind and when I express it I get “well what should I do” or “it not like that” I believe that for her but for him Ik he’s into her, not love but lust. Idk wtf to do.