Yeah I was all about the power in RSs so I've dealt with that in therapy too.
What my T showed me is that I can have the power/control over my actions and decision and so does he- having the power doesn't (shouldn't) mean that you have it over the other person too- that was such a relief, cause I was fighting for it soo hard because I thought that if I wouldn't have it that meant the other person would (and would be able to use it against me...)
However, from what you've written here I didn't get the impression that she wants you to relinquish your power but I kind of got the feeling like you would like to have it over her (which she rightfully refuses to let you).
I really hope you'll get what I'm trying to say- cause I know I'm babbling more than usual. But I like you CE and can clearly see how much you're struggling right now. Take care.