I think wives do "owe it" [to have sex with their husbands] to some degree. It's an obligation by default, because no wife has the "right" to expect her husband to remain faithful by being celibate. And so if extramarital affairs are against their morals, the wife is directly "forcing" the family to split up. You can only say the wife does not owe it if she does not owe her family any effort to preserve the family.
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).
ssmguy, I gather you have decided, at least for now, that you get enough out of your marriage that it is worth staying in it despite the lack of sex. Your wife, for her part, has decided that she'd rather risk losing you than have sex with you. I don't see how either one of you is forcing the other to do anything. Of course, there is a sense in which she is "forcing" you to choose between having sex and remaining married to her; but how does it really benefit you to look at it that way?
