I hear you, but given that being in love with one person seems to make me blind to other potential lovers, I think I may need to go a little bit outside my comfort zone here, or else I could be waiting for years to find out if having multiple intimate/sexual relationships is a possibility for me. And by "outside my comfort zone," I mean something like creating a profile on OkCupid and intentionally starting to meet polyamorous guys, as opposed to just waiting to find someone by chance.
I agree with ThatGirlInGray's perspective on this, but I should clarify my response: Go out and make friends within the poly community
if possible. That way you don't have the monostream expectations getting in your way, and the other poly's will be more likely to understand your situation.
(Was that the correct usage of "monostream," by the way?)