[BACKGROUND] My ex (we'll call Bob) and I dated seamlessly and faithfully for 2 years and then Bob asked me to marry him. I said yes. Sealing what was already a great relationship. And I was happy but not as happy as I should be. My parents and other immediate family were the first to point it out. But I kept at the relationship because Bob was an amazing person and I couldn't think of any reason I shouldn't be ecstatic. Well about 3 months out from the engagement I started to get really distant, studying in my education building (which I never did) and just trying to be alone, which I was, in the beginning. Then the guy (m, 22) I cheated with (we'll call him John) started to study with me. I caught interest and I knew John was interested too. Our study sessions, in public, went on for a while and we texted all the time, which Bob knew but I insisted we were just friends and would share me and John's conversation if Bob asked. But I started to feel bad about it because I could feel my feelings growing stronger for John, so I told John I couldn't see or talk him any more. I wanted my relationship to work, for Christ's sake I was engaged.
About a month later John and I had recontacted. A couple weeks after that, we ended up sleeping together. John asked if I was sure and if I was okay and I just said yes. But man was I wrong. When John and I departed he asked if I could not look so heartbroken but I didn't know how I could do that, I was heartbroken; this wasn't who I was.
Well then [shit hit the fan]. I didn't know what to do with myself, I lost control of who I was. I was drinking, not normal college drinking, on my own, sneakily, a lot. I would be with Bob and drink until I couldn't feel any more and then run away. I felt like I should die because of what I did to Bob. Most of the time I ran to John. Looking for a relationship or something more than sex that might justify me cheating on Bob. There was nothing. I stayed alive because I felt that the mental beating I was giving myself was worse than killing myself. Dying was too easy. John and I slept together more and I just kept pushing Bob away hoping he would just leave me. He didn't. He was a great person for putting up with me, I was extremely difficult.
John treated me awful (because, i'll be the first to admit it, I was insanely self destructive and reckless) and at one point I came to whatever sense I had left and stopped talking to and seeing him. I told Bob there had been someone else that I had feelings for, I told him it was John, but I wanted to fix Bob and I's relationship. Bob wanted to too. And I worked really really hard to try to build those amazing in love feelings that you should have with your fiancée but I just couldn't. Bob and I tried spending every second together then putting some distance between us. But nothing was working. We spent a lot of time talking one on one about our relationship. There were a lot of tears. About 4 months after I stopped seeing John, Bob and I decided that it just wasn't going to work. We remained friends and still touch base every now and then.
I never told Bob about physically cheating on him, it would damage him too much. I didn't want Bob to feel like there was something wrong with him or that he deserved it in any way, because he didn't. He's moved on and has a new girlfriend that seems crazy about him, just like he deserves.