Context here. We have been together for three years, and during the first section of our relationship, she talked me into an open relationship because she felt the need to explore further (I am his first serious boyfriend). I agreed because I didn't feel it was a bad idea, however, we established a core of ground rules: -1 No emotional involvement, only physical.-2 Complete transparency.-3 We both had a veto to stop it whenever they felt like it. During an exchange year, she started seeing a guy who, to my sense, was very much developing affection towards her: the guy did paintings on her, they met very frequently, and overall, I felt that she was distancing from me. I signaled my discomfort, and she said she would stop seeing the guy, while assuring me that nothing emotional had happened between them, and that he hadn't seen the guy in months. She also proposed to close the relationship, to which I agreed. Almost a year had passed, and she showed very strong signs of regret from that experience, overcompensating from what had happened, which made me alarm again: if nothing had happened, why did she feel so bad? Temptation took over me, and I checked her phone: I saw that she had erased the chat with the guy on one platform, just before a couple of weeks we had spent together during her gap year. In another platform, however... They shared clear signs of affection, saying "I love you" to each other, sharing ideas for their time in bed, and overall having a much closer and constant relationship she had initially told me they had. I don't know what to do.
I checked my girlfriend's phone (I know I shouldn't have) and I realized she cheated with me (during an open period of our relationship) What to do?
