I'm the male counterpart but I share some of the same feelings of inadequacy.
But it's strange that your feelings are fueled by
him "pushing" for sex and, in me, they're fueled by
avoidance of sex, "pity" sex, and "duty" sex.
The same feelings result from diametrically opposite actions on the part of our spouses.
And, sex is like Sominex to me, it results in quickly going to sleep. Even when I was young. This is an involuntary reaction of my body, not something I intend to do.