Tell him to stop being a sleaze, that if you don’t want sex he doesn’t get it. No sulking or moodiness, he graciously accepts that you don’t have to do anything you don’t want to do in bed.
If there’s anything he could be doing (more housework, more childcare, less going out boozing with mates, more compliments or affection etc.) that might make you feel more like sex then he needs to step up and pull his weight.
If he’s honestly the best he can be in all other respects, but you just have a lower sex drive, he needs to accept that and sort himself out.
Contrary to what some men try and make out, their balls don’t actually turn blue and fall off if they don’t get sex whenever they want it. And if they did, the same end result can be achieved with the use of his own hand without pestering you.
He needs to have a bit of respect and see you as an equal partner, not as a hole for him to stick it in.
If he can’t do that, leave him. His attitude is awful.