I should add that that doesn't fall just under sex but also the physical in the sense of not letting herself go, taking care to still be attractive to him, making sure he can still be proud to have her as his wife.
(within reasonable bounds of course, considering all the changes she goes through with childbearing and age, that's where his needs must mature and deepen as well)
I have known many modern women who scorn this and become selfish about what is convenient to them rather than what their husbands need, then they can't understand why he checks out and won't meet her emotional needs either. It's exactly as spouse says and it goes both ways, it's always a two-way street with these things.
I guess that does make sense to me, but in a more broad sense. It seems like if either of them let themselves go in any area of their life, they end up not being there for others and their spouse is sort of stuck with that for the rest of their life, if they don't stop it! So, in that sense, it makes complete sense to me. You know, you have a responsibility to your spouse to take care of yourself, because they depend on you and they are sort of "stuck with you."
In regards to "checking out," it seems like either can do that too. You start blowing off your spouse, then another words, you aren't making them much of a priority in your life and that's not right. They deserve that because of their position or "rank" in your life. It's like loving your neighbor. You don't have a closer neighbor than your spouse. So, to just kind of blow them off, seems pretty cold and of course, hypocritical.