All right, so here's my situation. I've been dating the same girl for the past two year. We both considered it a solid stable relationship and have made plans to eventually get married and have a family. A couple months ago she had sex with another guy. Normally I would just drop a girl like that on the spot and not think twice, but around the same time that she did that, I also cheated on her. If i had caught her cheating or she had caught me itd be over, but she actually confessed what she did, and I told her what i did. I feel like **** for having done that to her and she regrets everything on her part. My question is regarding the guy she cheated with. If he were a complete stranger just looking for a good time, I would just deal with her and let the situation with him drop. but its not. He doesnt know personally, but he knew she has a boyfriend. She talked to him about me, he saw me come to her job (they used to work together) and he even told her that he knew she was in a stable LTR. So, being that he knew all this and still disrespected me like that, I think he deserves a good ass beating. Would it be justified for me to do it?