Sexless Marriage (when one partner is ill)

I'm 38 going into a two year relationship with a 50 year old man. For the past 30 years he wasn't taking care of himself as he should, given his family history. He is overweight, diabetic, has been hospitalized for charcot foot all the while suffering with severe sleep apnea and doing nothing to fix it. Since we've been together I've been pushing him to see doctors and have them assess and treat as they see fit. I have never been treated so kindly and appreciatively than I have by this human being. He's an all around amazing person, and everyone loves him. Especially me! I have a, what I feel like is hyperactive sex drive. Simply put I love having sex! He, on the other hand seems to never want it until he gets tired of me borderline assaulting him. I'm not always asking for sex in the usual sense, I would be happy with oral or physically through touching. Anything at all would be better than the 5 year old that comes out when I try and initiate sex, which is often! Sometimes I cry about the lack of physical intimacy. I try to be understanding, considering the rapid decline in health in just one year. At age 49 he was taking care of himself eating right was pretty active. Then he turned 50 and it seemed like he just gave up and I can't understand why?! We argue about it often, nothing serious just frustrating. I love him with all my heart but I need to feel that sometimes too, not just hear it.