My (28M) girlfriend (26F) and I have been in a relationship for a few months now, and on the first few days of us getting to know each other I let it be known due to previous experiences in relationships that honesty and loyalty are my two biggest expectations for a partner. I also let it be known that a boundary for me is to not keep people around that you’ve had previous interest in romantically, or sexually and even though it can be normal for people to stay friends after that, it’s just something I’m not personally okay with. About a month in, she brought up a male friend of hers who she had met online and made a “joke” about how they had a marriage pact together, and I did vocalize that it had made me slightly uncomfortable and if the roles were reversed, I believe she’d feel the same way, and she agreed. After gaining this knowledge, I started having a little bit of worry on if she and this guy friend have ever had anything more, so I had asked her and she told me it’s never been anything more than just friends, no flirting, sexual things, etc. and I was just overthinking it too much, so I accepted it for a bit. A few weeks after, I started having a weird bit of anxiety and some nightmares on things with this, (and I typically have strong intuition) so I let her know what I was feeling, and I asked again if she was entirely honest, and she claimed she was, there was never anything more. So I let it go. Then once again, I started having a random panic attack one night while she was as at my apartment, and I had never went through her phone before, but something told me to check it and look at their messages. I fought with myself on it, but ended up looking briefly into them, and I wanted to be wrong but saw that a few weeks prior to meeting me, she had been talking about wanting to sleep with him, and that’s as far as I went before I felt so hurt. I woke her up and told her to be honest with me, if there had ever been anything more between them, to which she continued to lie, say I was being crazy, I was overthinking it, etc. She ended up “confessing” that last year they slightly flirted, and nothing more than that. Then it went on to they had flirted and had a thing for each other every time she wasn’t pursuing anything with anyone. And when I asked her to show me their message history, she got angry with me, and I admitted that I saw messages from right before we met with them being sexual with one another. She got mad at me and said it was a huge invasion of privacy, and I do agree it was to an extent, though she has told me if I ever needed to check her phone, she would be okay with it. But I set the boundary very early on that I don’t like my partners keeping people around they’ve had anything with previously, and I don’t like being lied to, and i had explained that if the roles were reversed, she would have been livid and tore into me over it. I don’t believe she has ever been unfaithful since we’ve been together, but the fact that she lied to me and made me feel like I was just crazy for having a gut feeling on this really hurts. She’s apologized and told me she didn’t want to hurt my feelings, and has blocked the guy on everything, but is also upset with me for still being hurt even though it’s so fresh. So I just really want to know if I’m in the wrong for how I handled things.