I got cheated on really early into the relationship with a guy I told her made me uncomfortable as she hooked up with him right before we got together but they were hanging out all the time because she struggles to make friends and he really understood her. She told me not to worry about it because “she chose me.” About a week and a half after she told me that she fucked him and she didn’t tell me till 3 months later. She said everything had been going too fast and she got freaked out, but says it was the worst mistake of her life. We agreed to try to make it work and she cut all contact with the guy. I really do love her and want to be together but in-spite of this, several months out I feel paranoid and insecure that she’ll just get tired of me and either leave me for, or cheat on me again with, a guy (I know how stupid it is that I care about the gender of this fictional person, but for some reason it matters.) I hate myself for feeling this way as she’s been amazing since and super understanding of how I feel, and I really do love her, it’s just hard to get past this fear/insecurity.