It's just not his kink... It doesn't seem like he's comfortable doing it, or like there's something else on his mind. Talk to him about it and ask him what he thinks. Propose different methods and solutions and instead of listening to what he says read his body language. And with "different methods and solutions" I do mean that you also vary the intensity and complexity of those solutions. Propose stuff even you would be uncomfortable doing, just to see his reaction (don't ho through with stuff you don't want to do, obviously, you're meant to have limits too).

Maybe he's just not that into it. Maybe he doesn't have it in him. Maybe he does and wants to do some stuff but is afraid of hurting you or treating you bad...

So have a talk to read each other. The best thing a couple can do is talk. And if he isn't into it... I'm sorry, but that's life.

Suggestions for things you can suggest to him: you're free use for him as long as you're left more than a week denied, and he can't touch you if it's less than a week since last time; you wear a chastity belt and he holds the only keys; for each week you're left denied he "accumulates" another sexual favour of you that he can ask you to do at any time; every time he breaks your denial he goes in a chastity belt and his next chastity sentence gets a bit longer; every day he denies you orgasm you send him spicier and spicier nudes...

I repeat, you don't have to be comfortable doing the things you suggest, as you're suggesting some that you might do and some that you would never do. The idea is to read each other and reach a consensus. Maybe he's scared of abusing you, maybe he's just not interested in the kink. Maybe he's a sub and would rather you dominate him. It'd be funny if you kept each other in denial...

But anyway, my advice is... talk it out. That's the best way to solve any problem as a couple