I (21f) accidentally read some of my girlfriend’s (22f) messages. Now I feel betrayed and have no idea what I’m supposed to do. Where I go from here?

My girlfriend and I have been together for about a year. I thought this relationship had been like a dream, we get along so well and she's really gorgeous, both with her personality and her looks. But I read some messages she had been sending to a friend, and I regret it more than anything. I was staying with her for a couple of days and my phone had died, and she said I could just use hers while she was in the shower. We often use each other’s phones, and I respect her privacy and would never read her notifications or anything like that and she knows that. But while I was reading something, a notification came up with my name in it, so I had a brief look at it out of interest. And what I read completely shocked me. Just a disclaimer that English is my third language, so I'm sorry if this is confusing in any way.

My girlfriend had gone through a phase when she was younger where she had a lot of casual sex. I had been aware of that, and previously I hadn’t been bothered by it. Where we live! has a very significant drinking culture, and so those sorts of things are bound to happen. I had never done anything like that, I didn’t mind that she had. She had told me the people that she had sex with, and they were mainly distant friends or other students. As far as I was aware, no people she is particularly close with or sees often. So really, I had no reason to be concerned. But reading through those messages, she had been talking to a friend about people she had sex with, and essentially rating it and them as a joke. It turns out there were several people she had slept with who she still sees often, and even stays with them sometimes.

And the stuff she said about me was really upsetting. She said I was so boring to have sex with, and that anyone would think I was a confused straight girl. She also said that my chest was so small, and that I look so straight and even taste straight. Which doesn't make any sense. Not to mention, she always has guys trying to hit on her and asking about her boyfriend, so clearly she looks straight too. And that isn't even a bad thing, I think she's beautiful. She also talked about some of her other friends, and how good they were at sex and how she'd sleep with them again if she wasn't dating me. She also talked a lot about a friend she sees a lot, and often stays with because she lives a far distance away, and she was going on about how it was the best sex she had ever had and how gorgeous she is.

I feel really numb. Not only because she had lied to me about something so significant, but also because she said those things about me. I have no idea what in the world I am supposed to do. I almost want to just forget about them, but I don't think I'll ever be able to see her the same again after finding out what she thinks of me. I love her so much, and our relationship had bought so much happiness to my life, but now I really don't know anymore.