Sex is only part... a great part, but only part of what makes a relationship work. Why do we get married? It's a ritual that confirms the bond between two people, and nothing more. A long term relationship can work without marriage, and the more I read your posts to do with the subject Tycho, the more I'm convinced that it's not the idea of "marriage" that bothers you, but rather "commitment" and "sharing." You have a very "only child" attitude about the whole thing... and you're obviously most unwilling to come to terms with the fact that once you've entered into a partnership with someone, you'll be required to give up some of the things that you hold dear.
But again, and getting back on topic, that's not necessarily true. This August will mark the 20th year that I've spent with my wife. Very early on I remember a situation where we were sitting around watching TV, and I got all excited because Star Trek (TOS) was on. She tells me, "Ehhh, I've never watched the show. I'm not into it." and suddenly I'm thinking, "Ouch! That's a big problem." I could let a lot of things slide, and frankly she's not a huge Star Wars fan either, but Star Trek is something entirely different.
So... I forced her to watch this day long marathon with me, and after just one or two episodes, she "got it." She's been a fan of the show ever since, loving it for the campy, corn-ball, bundle of Sci-Fi brilliance that it is. As a matter of fact, it was my wife (then girlfriend) that got us into watching TNG, and was the one who started buying all of the Playmates figures that we have. Initially I was going to pass on them, but she pushed it, and I'm glad she did.
So Tycho, it is possible to find someone that puts up with your kook lifestyle. It's only a matter of deciding how much effort you want to spend to make it work.
And last word: attitude. It's fine being cynical or pessimistic, but only to a point. I know that at this time in your life you're more concerned with how much time you've got left. But you've fought that battle with a wild amount of enthusiasm, and I can't see why you're so willing to admit defeat when it comes to finding someone to share your life.
You know... live long and prosper.