Originally Posted by kittyb
... except for sex
... at the same time I feel lonely and unfulfilled
Not to be a downer (I'd be great if polyamory filled all of your gaps), but... You know there are other fish in the sea, right?
I realize that on a poly board, poly may seem like a solution to a lot of things, but there's also the old-fashioned breakup to consider. Maybe you stay good friends so you can continue to share interests together.
In my experience, goals and interests (which are the good points of your relationship) tend to coalesce between two people over time anyway. So it seems like you might be happier in the long run with someone whose time and sex habits align with yours, even if he doesn't start out as your political debater.
Besides, if you want sex 3 times a week, you're going to be spending an awful lot of time with someone else. Not that that doesn't work for people, it's just no small thing you're undertaking here.