Am I overreacting?

[Xxtrinity1991]

I want to know whether I'm crazy or not. So me and my girlfriend had a threesome with one of our friends. After that we ended up going through problems because she messaged that girl and was flirting with her saying she wants to hook up again. She deleted the text before I saw it bit I msged that girl and she sent me the whole convo. My girlfriend told me she was just drunk and that she didn't mean it. Anyways a couple months after that me and my girlfriend were going through problems again she left me crying in a parking lott because she had to pick up that girl that we had a threesome with. She continuously arguing saYing that it's not a big deal and that im over reacting. Today me and my girlfriend are doing well however this girl comes around our friend group sometimes and I feel really uncomfortable when she's around so I try to avoid showing up when I know she's going to be there. My girlfriend gets mad at me saying that I'm immature that she same doesn't have feelings for this girl and that I need to get over it. I'm not starting any problems with this girl but I would rather not be around her. Am I overreacting?

[MartinOhm]

If you do not feel comfortable around that girl then the best is to not have any contact with her; and while it seems you are doing great with your gf; maybe it is time for both of you to get in separated ways if that girl is going to be a hugh part of her life for some reason. Well I do not know any of you in person, so I do not know if you are overreacting or not, but the safe bet is to stop having contact with that girl and to some extent with your gf if it is necessary.

[Hooo!]

is there anything wrong with the girl?
I dont understand what you are avoing her for exactly?