I completely understand -- and you have the answer yourself. You said that you don't necessarily want a relationship with them, but you don't want them to have one cause you'll get "demoted" as not a "close friend" anymore. I can understand that.

And I don't think it's weird or anything. I'll bet lots of folks have felt like that before.
But if your friends are any kind of friends at all, they'll still keep you in the loop of friends that they have. You'll still be invited to parties, or get-togethers. It doesn't matter that you're single -- if they're REAL friends, they'll still want you around!

So no problem, right?
And you'll find the right girl soon. Just don't "settle" in order to have a relationship. "Settling" is the worst thing you could do, and isn't fair to you or the person you choose. Wait for the RIGHT one -- you'll find her. Just be patient -- she's out there.
In the meantime, enjoy your friends and stop worrying. You're not going to be forgotten, believe me. You're a good guy. Hugs, Lee