I sympathise. Most people who know me also know my boyfriend, and they rarely if ever treat me as a sexual being. It's very disheartening, if I was male I would probably feel castrated, I'm not sure what the equivalent would be here (am I missing my breasts or my ovaries). At any rate, I feel like people I'm interested in are just so used to treating me not like a woman, but like a person without gender, that they wouldn't even consider me as a partner.
But if it is known that I am polyamorous, it's even worse, as they assume I only want casual sex with others, and that I want it with everyone. Those who want something serious start to avoid me, probably because they're worried I'll try to corrupt them or something, and others just expect sex from me, sometimes people I don't even know!
It's frustrating, but still, it's who I am. It sucks that society doesn't get it, but it's not our fault.
In your case, it seems you don't have any partners right now, which presents its own set of difficulty of course (for instance, if you do find a partner, they might assume you'll change your mind once it's serious with them, and be heartbroken when you don't. At least I don't run that risk).