I don't really disagree with anything you have said, but I strongly disagree with the post I was replying to, in particular

If your spouse's desire to have sex is greater than your desire NOT to have sex (for whatever given reason, which may or may not include practical reasons and/or "not feeling like it"), then you should have sex with them.

Its just a terrible, terrible attitude towards something that people so often seem to hold, and when it boils down to it, it comes across as entitlement.

The point I'm trying to make is that one day, even after 30+ years of marriage and regular sex, one partner can decide that they don't want to have sex any more. Sure, the other partner can be upset about it, but at the end of the day there isn't anything they can do to change that.

A relationship isn't a system of contracts and obligations. Its a partnership, you're supposed to help each other. When someone enters a relationship bringing preconceived notions of entitlement towards their partner, then they shouldn't be surprised if the relationship breaks down.

I agree that in this particular case we don't have enough information, but what I'm saying isn't about this case in particular. Its about relationships in general. My initial comment in this thread was

Why?
Does sex become an obligation after marriage?

Which was also downvoted, and the only response being from the guy who replied with

If your spouse's desire to have sex is greater than your desire NOT to have sex...then you should have sex with them.

Which can only really lead me to believe that people here have an extremely poor idea of what it is to be in a relationship, which I find quite sad, because if that's the attitude that people are carrying into relationships then I'm not surprised why so many relationships breakdown and fail.