It's interesting that he keeps asking what you want. Manipulative people will glean information from their date or object of affection and "chameleon" themselves to win the prize.
Also -- when I was married to a manipulative A, this question "what do you want" was in order for him to be able to abide by the
word of what I expressed, not the spirit. For example, if I said "I want to be able to hang out with my friends without you yelling at me about it" -- he would not YELL, he would just quietly ask when I got home "so how many guys did you f***? were they better than me?" etc. When I pointed out this was exactly what I was trying to avoid, he'd say "NO -- you just told me you didn't want me YELLING at you..." and so he could conclude that my "want" was a moving goal that he would never be able to live up to and that I was just trying to manipulate and control him.
I think your response was perfect. You want consistency. Predictability.
Question is if you will ever be able to get that from a person who doesn't understand the request.