I am leery of discourse about relationships that focuses on what each partner "owes" the other because it is often an excuse for not making hard choices and taking responsibility for them. A wise person once posted that the universe of things your wife owes you can be divided into two categories: those things a court would order her to give you if you divorced, and those things that she doesn't actually owe you. The question isn't whether your wife owes you sex; it's whether you owe it to yourself to be with someone who wants to have sex with you (for whatever reason). Phrasing it that way forces you to take responsibility for your choice to either remain in your marriage or to leave it. Your wife, of course, must take responsiblity for her own choices (and their consequences).
EXACTLY!
SSM is a glaring signal that a marriage is not succeeding. Some posters here seem to suggest that if the wife, in these cases, would just satisfy her H's sexual needs, their marriage would continue just fine. Not so! That would be to completely ignore the message her inability to have sex is actually sending: "Something is seriously wrong in my life and I'm in pain." There are critical issues--whether the couple has learned to communicate, whether they actually love each other any more, whether they know how to meet each other's basic needs--which must be addressed first.
Not feeding the children is not a very useful analogy for not having sex with one's husband. And not because the H is not going to die without sex, but because, unlike the children, he's exercising his choice in choosing to see himself as a helpless victim rather than a participant in an unhealthy union.