Quote: What does desire for change have to do with anything?
HP, that's how I see it as well. There is no need to make it a sexual desire issue. It is an issue of when two people live together and have a relationship, there have to be accommodations. And the accommodation cannot all be one-sided.
It's not an issue of whether or not she wants to be a better lover. On things like position switches, next time you get a "let's just do it this way" a kind, gentle, yet assertive "I would rather not this time, I would prefer to X". The crap may hit the fan, but the stalemate will be pushed a bit.