I'm not going to read what Mono said until I post as I have some ideas from reading what you said and may come back afterwards if I think of something after reading Mono's.
I wonder if he would really prefer you explore some of what you want to explore with him but is having a hard time managing to get to it, due to his health. Perhaps he is aware of that, but feeling inadequate as a lover and therefore struggling to request it of you?
Maybe it's time to shake things up again and see what happens... he might not be saying no or yes, one way or the other, because if he felt connected and close to you (in love) then he would be okay with your exploration and would be willing to let you get out there as a way to enhance your sex life together...
I guess what I didn't read in your post was much on what he has said and more on what you want. What you desire and are feeling rather frantic to have by now... understandable, but perhaps backing up and getting him out of his shell about it would be fruitful...
just a thought...
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