Everyone knows the health angles. Have you tried talking to him about how his habit turns you off? Don't the teeth turn yellow/brown (and later fall out), gums bleed, breath stinks, remnants are around, etc.? Does that sort of interfere with how attracted you are to him physically? That would be an issue for me. Besides the health implications.
Kurt Schilling is a retired MLB pitcher who has battled his addiction to chewing tobacco and survived a case of oral cancer a few years ago. I've read some of his writings about it. I thought I'd share this one, which I think is particularly poignant:
https://www.theplayerstribune.com/en-us/articles/curt-schilling-letter-to-my-younger-self
Good luck, I hope your husband can find a way to finally quit once and for all.
Would you say the same thing to your spouse if they were overweight when you married them, they lost weight and then gained it back?