Geminigirl basically said most of what I was going to.
1- If you see this person once a week, there's no reason that on those other 6 days a week why you can't be going out dating (just like most single people do, poly or mono) and eventually meet that ideal primary partner.
2- Until that happens, make yourself your own primary. (This is where I currently am myself.)
3- Get some hobbies and friends that share those hobbies to fill up any alone time.
I've been single for six months now about and while I haven't met anyone that I can see as a primary, there are two that I can visualize being a secondary partner to. And that's great---that's better than completely single, ya know? I say while you work to find your ultimate goal, there's no reason not to enjoy what you DO have!