I respectfully disagree with Mr. BruceBoxer's analysis, although I can see where he's coming from. I suppose even I would question the self esteem of a woman (or man) who desires to be a 24/7 sex slave. There I might even consider that there are far deeper issues than self esteem alone. And I'm talking about someone who truly seeks that kind of relationship...not the ones who fantasize about it.
On the other hand, I am sure there are plenty of sexual submissives who suffer esteem issues, just as a percentage of any sub group of our population does. At the same time, I think there is an equal percentage of sexual submissives who are just the opposite. I have met many women over the years who are genuinely self confident, strong and carry an important position in the workplace...but who seek a submissive role in the bedroom. It has surprised me on more than one occassion.
My personal sub basically took me by the balls and told me what she wanted and how she wanted to be treated. She didn't know that I would react favorably (which I did) and she jeapordized a relationship that is very important to her in an effort to improve it. I think that shows a lot of self confidence and high self esteem.