Has anyone here ever have trouble staying aroused or becoming bored during sexual activity with a partner (or even on one's own)?

I haven't had a partner in about 2 years, but when I did, this was often an issue for me. It still is on my own and I avoid any sexual activity (by myself) unless arousal is strong enough that I can't ignore it. I was way more excited about sexual activity with a partner (and almost always initiated) even though it didn't really work at least partly because of the above problem. Now that I'm on my own, I often wonder what the point is. I don't need the frustration of getting aroused and trying to stay aroused and not get bored long enough to get any sort of satisfaction. It's even more frustrating to have to ignore when I am aroused because I can't do anything about it without it ending up being frustrating and empty.

I've only had one partner that I was with more than once, so I'm not sure if it's my fault or I'm not attractive enough to attract someone I'm attracted enough to or if there's some other problem.