So the wife is less committed to her sex part of the deal than the husband is to most of his parts. The wife can implicitly threaten to withhold sex for last minute demands, but even if he meets those demands she may still decline. And if she is not in the mood there is little he can threaten to withhold at the last minute that is of comparable value. Without kids he might threaten to leave the marriage, but that is a dangerous game to play.
Presumably overall this problem makes men less, and women more, willing to marry, though it may also make men more eager to marry to signal their confidence that this problem won’t befall them. I see two general ways to avoid this time-inconsistency problem:
1. Obligatory Sex – more explicit norms about the frequency and nature of sex, norms wives are expected to meet even when less in the mood. Perhaps wives would have to do something unpleasant, like exercise lots, when there was no sex.
2. Nonobligatory Other – remove something wives want lots from the usual set of stable husband contributions, so husbands can threaten to withhold that without being a pariah. Perhaps the expectation that he sleep at home [added: or maybe a big budget he could spend on extras for him or her]?
Both these approaches have been common in the past. Either would make women less willing to marry. Men won’t propose these because that would signal a lack of confidence, but women could propose them to signal they don’t expect a sex problem. Intuitively this seems unlikely, thought I’m not sure exactly why.
Added 3p: I’ve said it before, and I’ll say it again: people express strikingly little sympathy for sex-starved men.
This was really funny. Poor sex starved married guy.