Talia, it sounds like this is a relationship problem, not a D/s problem.

I agree with a lot of what others have said--topping from the bottom, for whatever reason, is when the sub takes control of the situation. Maybe misbehaving to earn a "punishment" (presumably something fun). There is indeed a fine line between being playful and being manipulative, and I suppose it's different for every couple.

Had you met him at the door, on your knees, begging to play, he might have ignored you just to tease you or to reassert his power (we'll play when I say so).

But unless I misunderstand the situation, you weren't asking to play. You were asking for something you need in your relationship, and I think regardless of your power dynamic, it's a request he must take seriously. Personally, I don't think it's acceptable for a person to be cruel in a relationship just because they're the "top."