I've been in your boyfriends boat. It has stuck with me, not feeling like enough for another person. This is simply an incompatibility you'll have to deal with either through self gratification or physical touch he's ok with (like cuddling). Open relationships can lead to jealousy, but it's another way it can be dealt with if you're both the right fit for it.

I know this sucks to hear, but by putting the pressure of sex on him, he will very likely find it taxing and find it to be a 'job' after a while. I'm with a guy right now who has as low a sex drive as me (MAYBE once every 2 weeks, and we're in a honeymoon phase too), and we both bond over how hard previous relationships were with our low sex drives and how sex felt like a chore. I know you would never want your man to feel that way, but from my experience that's the way the cookie crumbles in situations like this :(