Well - as you referred to in your comment, there certainly are different "levels" so to speak - 24/7 Master/Slave vs a relationship that is just a little dom/sub...
I think many people get involved in relationships with a dom/sub structure, but not willingly (i.e. controlling/manipulative abusive husband, etc).
Anybody been involved in a relationship that was unique to you in that you or your partner willingly gave up the power to the other?
yes?