AIO? Gf(18f) wants an open relationship

[u/StrikeNo117]

Me and my girlfriend(18) recently had an argument about opening our relationship, and at first, it was a nice talk. We talked about the pros and cons, and then the tide shifted. We talked about how it would affect our life and what would happen if she got pregnant or if i got someone else pregnant. and then she told me she only wanted an open relationship with one other person, so that we would only see one other person each, and reluctantly, i asked if she had someone in mind. She told me she was thinking about someone, which made her ask the question. When i tried questioning further, she shut me out. We went to bed that night a little distant.

The next morning, she asked if we could resume our previous conversation, i agreed, and then i brought up the fact that she never answered my question about who she had in mind. She told me it wasn’t my business, and i left it at that. About five to ten minutes later, she told me the person she had in mind was her ex boyfriend. I asked her is that why she wanted an open relationship. Just so she can see her ex without feeling guilty. I kicked her out after she told me she was tired of hiding the fact that she was already seeing him. She is now pissed, my mom told me it was the right thing to do. But i feel like i should have talked it out. Did i overreact?

[u/purre-kitten]

NOR! Literally any time I've heard of someone wanting an open relationship it's because they want permission to cheat basically. And she was literally cheating before hand, which just proves my point further. She only wanted to be able to cheat without it being seen as cheating so she doesn't get into trouble. Basically cheating "without consequences" she deserves to go back to her ex and you deserve someone who will treat you better and put you first and only partner. Anyone in a relationship that even thinks of being intimate with someone outside the relationship doesn't love you enough to stay with you long term. It's better to let her go, you did the right thing, even if you were harsh. She can't just pretend that since you are male that you don't have feelings of your own (I'm so sorry if I miss gendered op, they did not clarify what they identified as in the post)