Sorry for any grammar mistakes I’m writing this on a phone. I(18M) have been dating my gf(18F) for 9 months. She was perfect! Having lots of similar hobbies and likes, same views on most things. Her parents loved me and always asked me to come over. We instantly hit it off. In my mind she could be the one I wanted to spend my life with. Everything was great in our relationship until 3 months ago when I felt she was pulling away a bit. I asked her and talked but she said nothing was happening and stated that she was busy and stressed and maybe me feel guilty about asking her. She promised that it will get better. But not only did nothing get better, it got even worse. She basically ghosted me on everything and only would respond in group chats. No amount of talking it out or trying different relationships advice would help me. But I supported her in and out believing her and apologizing when she said I was overthinking. Then last week I went on a out of state trip to meet my family. She didn’t return any of my texts. Then on the last night before I was supposed to return I got a dm from a girl I didn’t know. She told me that her best friends boyfriend cheated on her with my gf. They sent and received nudes. I got pictures of the text messages calling out my gf. (On a side note my last relationship my ex-gf cheated on me and my current gf knew this and know how destroyed I was and that cheating was unforgivable.) I was sick to my stomach, couldn’t sleep, and a raged that made my mind explode. I treated her like a Queen, I gave her my all and let myself be voluble to her and she stabbed me in the heart. I am torn, I’m disgusted by her but still love her. Before I make my decision I want to know more, I want to be 100% sure about this. I used my good connection with her mom to find out her schedule in secret without telling her what I found out. I am going to plan a “date” for us alone where I am going to confront her and demand to know her side and to see all of her phone. If she doesn’t give me her phone that as much proof as I need to know she is cheating. Because at the start of the relationship she wanted us to have a open phone relationship where we both have the password for each other phone. But I want to hear other opinions and suggestions on how to deal with this. None of my plan are set in stone yet, and I will be texting her mom tomorrow to get information about her schedule. But at this point I don’t want to see her until then. Please help!