It sounds to me like his "not in the mood" mood has lasted for a short period of time. If that is the case, just wait till it passes.

Sometimes it can be very difficult to be patient. I know; patience is a thing I have no experience with. Though it happened only once, there was a time that I was not in the mood and my sub was very in the mood. He pestered me to the point that it got annoying and I yelled at him and we had a huge argument, and I said to him "I don't think I have ever told you 'no' before, so if I'm saying 'no' then I fucking mean it!" It wasn't pretty. He apologized for days. He never got pushy with me again. It is as you described; I can probably count on one hand the number of times in a year I don't feel like sex. Most of the time I want it and he might not, but that's not important, I get it anyway. But those are our natures.

We doms are not like subs. You don't tell us what to do. Don't push a dom unless you want to be pushed back. Expect to be pushed hard and in unpleasant ways.

Or, you can just be patient. He'll want you.

You could possibly also ask for permission to masturbate; that might give him relief if he's feeling guilty about not being "in the mood", and it will help you tide over.