So I'm gonna start this off with yes this is a throwaway, he uses Reddit. I'll also say I know I shouldn't have been snooping though his stuff without him knowing but I did. I fully admit I'm wrong there. So when I was snooping, I found he took a picture of another girls butt, clearly without her knowledge. I called him out on it and he pretty much just shut down. After we talked for a bit, I ultimately said "Do it again and I will break up with you on the spot." I also said I would tell his family and some of his friends if he did it again. My mom said I shouldn't have threatened him like that but I felt like I just set a boundary.

Edit: I just want to say I really doing know what to do here. I know I'm in the wrong but I feel he is too...