How can I get my husband to shower more?

I can only get my husband to shower once a week. He has diabetes and thyroid problems so he sweats more than usual. I've tried everything, including refusing to sleep with him until he showers. He hates bathing too, so that's not an option.This has affected our sex life, because I can't make love to someone who smells sweaty! Please help! I've even asked him why and he won't give me an answer.