Girlfriend is still friends with her ex

Relationship Questions and AdviceCategory: CommitmentGirlfriend is still friends with her ex
Zach asked 9 months ago

My gf is still close friends with her ex. She says they never dated, but she used him to cheat on past boyfriends she didn’t like so I consider him an ex. She insists I’m different and she wouldn’t do that with me, and I believe her. She likes going to his place and hanging with him and a couple other of their friends that I don’t know without me there. She knows I don’t like that but gets mad at me when I confront her about it. I always assure her it’s because I don’t trust him, not because I don’t trust her. Is it fair of me to want her to stop talking to or hanging with him? I honestly need advice, cause I really don’t know if I’m at fault or she is. If it’s me, I’ll work on my issues no questions asked. I just don’t feel like it’s unfair of me to ask that seeing as she has a long history with him and cheating on her past bf’s with him. If she truly wants a future with me, she’ll stop associating with him, right?