There are a lot of complicated issues in there. You're going to fit right in.
First of all, it's not your fault that your desire levels are different. The first thing is that assuming that your H isn't gay or isn't intentionally using sex (or lack of it) to punish you, you need to accept is that you simply have different desire levels. It's not that you're unattractive. It's not that you're undesireable. You're sex drives are just at different levels. You did't say how bad the problem really is, just that you're HD and he's LD - both relative terms. I'm assuming from other things you've said that you do ML at least once in a while.
The next issue is taking care of your own needs, and you've raised multiple issues there. If you believe that he feels pressured and that the pressure is contributing to his not wanting sex, then backing off and taking care of your own needs may be a viable stopgap. What catches my attention though is your statement that you're afraid you'll do that, then he'll be interested, and you won't. Simple question: would you be unable to respond?
You say that you feel like he takes care of himself instead of coming to you. Do you know that? We have an entirely different issue here if the LD partner is not only LD, but also directing that lower desire somewhere else other than to you. In a case like that there's more going on than a simple difference in levels of desire.
I won't wade into the issue of turning him down when HE wants it. That one's way too sticky for me.
