Suggestions ...?

So. My long term boyfriend and I have been having a bit of a dry spell in the bedroom. We’ve been together for 4 years and in the last 2 years I’ve seen his sex drive decrease more and more and I feel like I’m begging him for sex. I’ve tried talking to him about it. I feel like total shit when he denies me. He went to a doctor and had bloodwork done because I raised my concerns. His Vitamin D was extremely low (which can be a cause of decreased sex drive) and he now takes a weekly pill. I’ve seen an amazing increase in his mood and sleep habits but still no luck in the bedroom. What can I do ? Or what should we do ?