O.O.
You say he's "sick." We don't know what that means: cancer, the flu, Lyme disease, heart transplant...
If it seems to you that his sex drive is improving as his health improves, then it's likely it will continue to do so, right?
I don't mean this to sound snarky, but if he's "sick" then his health is the important issue. If you've been married for any length if time, you probably already know about and have experienced some "peaks and valleys" with each if your sex drives. Maybe before you lost weight, you weren't as interested? So how did your husband handle his end then? Is it necessary that he knows when you TCB? If it makes him feel bad, why share that?
Seems like your particular issue isn't "spicing it up" it's just a frequency imbalance.