I cheated on an ex for suddenly ceasing all sexual contact for months on end when I was a little younger than you... 20, I believe. I thought at the time I was doing would help preserve our relationship for selfish reasons, and I felt as though it would be emasculating to break up with him on such terms for slightly less selfish ones. But to be clear, I wanted to keep him in my life because he was really awesome and I thought he'd be the one for me, if only we could fix the one small problem between us, and in the meantime I would get my needs discreetly met.

It's been about half a decade since I made that choice, so I've had a lot of time to reflect on it. The truth is that even though he was selfish for expecting me to remain faithful despite him unilaterally deciding to change a fundamental part of our relationship, it did not change the hideousness of my actions- I was keeping him with me under a farce, and the huge secret I was keeping led to way more anguish than it was worth, even though he never found out. In the end, it rotted the relationship to the core- I could not be with him without feeling guilty or afraid he'd discover what I'd done. It was with me every second of every moment we were together.

What I ought to have done was either decide to deal with the issue and be faithful regardless, or break up with them. Cheating is the coward's way out, it's only really understandable in a few niche circumstances. You don't want to either acknowledge that sex is either a big enough deal that a lack of it would drive you to betrayal, or that your communication isn't good enough to work this out.

My ex was/is a great guy, very funny, intelligent, attractive, and insightful. But he still wasn't the guy for me, and cheating was a way of denying that to myself.