My boyfriend and I have been together for quite a while now, but there was a point where we were hardly having any sex (like once a month), and he basically dismissed it as him being tired from work. This went on for about four months until I finally told him I wanted to try an open relationship because I wanted to have actual sex, not just jerk off, and if he wasn't going to have sex with me anymore, then the step before breaking up (because oddly, everything else in the relationship was great, just no sex) would be to at least try an open relationship. He said I could go ahead but just not tell him. So, not really cheating, but it still did feel like cheating because I knew I was the only one doing anything, but I did have his permission.
So, I slept with a few other guys (actual anal sex with just two, and then oral/mutual jerking off with three), and never told him, but I noticed almost immediately that any time I met one of the other guys, I felt such a horniness that I hadn't felt in such a long time. It was then that I finally understood that whole "new" feeling that people crave and perhaps is what attracts people so much to new porn instead of using the same porn over and over.
The thing that surprised me, though, was with the five guys I had met with, I only left actually satisfied or having enjoyed the experience with one. Not that I left necessarily disappointed (and there's no real point in delving into what made each experience slightly dissatisfactory), but it did make me realize that as horny as I am/was, as much as I wanted physical touch from another man and all those things, it wasn't like just having random sex with someone would miraculously be what I had been dreaming of. I still had that like '... but... now what?' sort of feeling. Only the one guy (who was actually the first guy I had met) had been like, perfect.
Since then, my boyfriend and I have been more sexually active, but he's basically told me that for the time being, basically until he finds a different job or gets promoted, he is physically too drained to have sex regularly, and so I can continue to meet whoever I want. Just as long as I always return to him. And oddly, there's something so nice about that. I love him, but even when we first met, it was obvious that I had a way higher libido than him. So I can appreciate him letting me do this. And so I only meet the one guy every few weeks or so, and that's it. I get the whole wanting to cheat even within a long-term relationship. People judge and hate and criticise but I really do get it.