The nuance is that there can be a tension between commitment to a relationship and individual autonomy. Nobody is entitled to sex from another person, married or otherwise, and nobody is entitled to make their partner do something they don't consent to.
But I think there's a distinction between being entitled to a particular act and having reasonable expectations of a relationship. A spouse can reasonably expect things from a marriage — companionship, reliability, emotional support, affection, sex, financial or practical contribution, whatever it may be — without being entitled to demand any one of those things on a particular occasion.
Relationships, and particularly marriages, are reciprocal. We routinely do things for our partners that wouldn't necessarily be our first choice because compromise and consideration for another person are part of being in a relationship. Both people get things from the relationship and both put things into it. Autonomy means you ultimately decide what you do, but it doesn't mean your choices exist in a vacuum or that your partner can't have expectations or feelings about them.
And before somebody translates that into "women should have sex when they don't want to" or worse, that isn't what I'm saying. Again, that is bot what I'm saying. Consent is still consent. Nobody is obliged to have sex on any particular occasion.
My point is that "you cannot compel somebody to do X" and "X can never be a reasonable expectation within a marriage" are two different propositions.
I'm also not commenting specifically on the OP's marriage or defending her husband's behaviour. I'm making a general point. "Sex is your job" is far too simplistic, but so is the idea that marriage consists entirely of two autonomous individuals who never owe each other consideration, compromise or effort.
Commitment, expectations, reciprocity and personal autonomy all exist at the same time. That's the nuance.