One might suspect that the housework-sex connection was related to couples' views of appropriate gender roles.
WSJ: The Sex-Housework Link
2.
The images promote the message that single people, unmarried couples, same sex couples, over 40s and non-home owners can all have roles to play.
BBC: City Chambers projection
3.
The placement of a hand or positioning of the groom contains assumptions about physicality and gender roles that often don't apply to same-sex couples or even nontraditional straight couples.