My feeling is that if you are "looking" for people, it tends to not happen. I've had the same issues (and I'm a girl!), and I'm starting to just let it go and instead of looking for people to meet, I'm just trying to get out more, and get more involved with activities I love and eventually I figure I'll meet someone that way.
I see a lot of people come on the board who have opened up their relationship and are now "looking" for someone. And I truly believe that like with most things, you have to let it happen more organically.
You might try getting involved in the local poly scene just to be around like-minded folks and see how that goes...