Obvi it was a shitty thing to do but sometimes I think about it and it’s gets me so worked up. Old story but me and my ex, we’ll call her Sarah, used to share a coed college dorm room together. We had an open relationship so we’d have threesomes together and have our own individual hookups. Our only rule was the other person has to know. One night I snuck out of our bed to hook up with a girl I matched with on tinder and omfg was it some of the best sex I’ve ever had (I’ll tell you about it). Sarah woke up, found me missing, and started calling me. After seeing Sarah call my phone ringing me and my hookup started fucking harder obvi turned on at pissing my gf off. After getting back me and Sarah fought for a few days but ended up together again (and had a few more threesomes). We’ve broken up recently but this story sticks in my mind. Yes I know it was terrible to do but fuck did it drive me crazy