This question isn’t hypothetical for me. A couple months ago I met a great guy and we went on a couple dates. As we got to know each other, he told me more about himself. He has a severe case of depression that has come and gone all his life. Due to that and the antidepressants he has a very low sex drive and doesn’t date often (but he thought I was so “compelling and confident” that he wanted to get to know me better.)
He was the one who broke it off, but then we stayed in touch and ended up becoming friends. He’s smart, nice, and interesting, and we call each other every couple days and hang out every week or two. This friendship feels a lot like early-stage dating, except there’s no expectation for things to escalate through the steps of dating (like spending more time together, declaring your feelings, moving in together, or whatever). It’s also different from my friendships with other guy friends. Most of my guy friends are casual buddies, like the kind you hang out with at group get togethers sometimes. He’s become part of my inner circle, and we have real conversations.
So… I don’t know. I have a very minimal urge to date these days anyway, but it seems like it would take a LOT of mutual respect for people with mismatched sex drives to make it work. There seem to be a lot of people out there who are not in mutually respectful relationships and can’t even handle regular dating. I was in relationships with people who had a higher sex drive and always made me feel guilty and like I “owed” them sex, and it was awful. The other side of the coin is the desperate people in places like r/deadbedrooms (a subreddit & one of the saddest things I’ve ever read.)
A carefully-negotiated open relationship sounds like a good answer for the romantic side of things. And lots and LOTS of mutual respect and empathy. I think with those two qualities, just about any couple can be happy. For me and my friend, just being friends has been a very positive outcome.