Hi Betty!
Here is another perspective that might help out.
First off, I too am an assertive woman, I operate a business with my husband. I work alone (except for my husband) and therefore don't have to contend with coworkers. But if I had employees to watch over, I'd be much different with them than with people I choose to socialize with.
I know a lot of women who have a persona in the work place that is perfect for getting the job done, however, in social settings would seem stiff or cold. Maybe this is getting in your way.
When going out to meet potential swingers you might think about how you carry yourself, how much smiling you do, how spontaneous you are, whether you are relaxed and free with your gestures. In business staying more controlled can be an asset when negotiating and holding your place of "power." But outside the workplace it may hinder you; you may be appearing rigid. This may not be your situation, but I wanted to bring it up because I've seen this happen with women--even in vanilla social gatherings--and it makes them less fun to be around.
To answer your questions:
1. There are plenty of men and women who LOVE assertive women as playmates, as others have stated. So don't shut your assertiveness down, just make sure you're warming it up with a smile and some flirting! Initiate!
2. I think your paranoia is unfounded. It does take time to find couples. Be patient.
3. Should you be doing something different? If you feel you're coming across as approachable as you can, great, if not, maybe there is room to warm up your swinger image.
Happy swinging!
LM