Then wifey starts seeing hubby as a sexless entity --- sort of like the son she never gave birth to --- and loses attraction for him.
"... it isn't a gender thing. It is a money thing"
Humans spent millennia as hunter-gatherers. Men hunted, women gathered. Men protected and provided, women nurtured the children. If women provide and protection is provided by the state, then men are useless. Birth rates fall. Religious people who live according to traditional gender roles then outbreed the atheists.