I know what you mean. Coming out as a lesbian to my family and friends was a piece of cake compared to coming out a poly. Every single person I've spoken with doesn't understand what it really is and often confuse it with polygamy. It is so hard to get people to understand you really can love more than one person at the same time. Anyway, I'm a bit off on a tangent there. To your question, is it possible to maybe try to become friends with people on places like ok cupid first and then explain your situation? They might be more willing to listen then. I wouldn't get involved romantically though without being honest about your situation. I think it would only lead to disaster, but that's just my opinion.
Best of luck to you both!