u/Basic-Veterinarian49

I M22 have been with my girlfriend F20 for around 5 months now, a month before we got together she had a one night stand that for some reason I just can't get over, prior to her I had 0 sexual experience so I'm sure it plays some part but I just can't get the situation out of my head. No matter what I try I keep visioning it in my head and sort of comparing myself to him despite the fact she's now with me and we're extremely happy but now I feel like this issue I'm having is making me feel like I'm going to self sabotage our relationship over something I can't control and it isn't fair for me to make it her issue. Has anyone had anything like this?