Is a person who "goes through the motions" of sex just to placate their partner prostituting themselves?
First of all, you said "partner" so I'm assuming you are talking relationships. I've been married for 3 decades and we are not always "in sync". But I never feel like I am prostituting myself. Making him feel good invariably makes me feel good too!
If he was a jerk and forcibly took what he needed after being told "no", which does happen unfortunately, in our world. Then I don't doubt a woman could feel used. Ever hear of feeling like a "hole in the mattress"? That's not affirming