Women aren't withholding sex, wives are withholding sex from their husbands.
Briffaults law, western women gain nothing from having sex with their husbands (as they already own all he has and all he will earn) so there will be no sex.
I had no problems banging my neighbours wife, daughters, women I met in the pub, friends wives, etc. as they still saw potential gain from the act.
Sorry Jim, but you don't have a clue about female motivation, and in the end that's what defines the losers in these situations.
As for when this started .... In the UK it was 1997 when the laws were changed to allow rape within marriage, before that a husband didn't need consent.