John is worried about being too rough with Mary while she's pregnant, but as soon as the baby is delivered, all bets are off, and she's going to pay for lying to him for so long.

Just to keep track (and make sure he doesn't forget ANY of it), John keeps a list of all the sexual things he's going to do to Mary pinned to the fridge of their flat, waiting for the baby to be born so he can start checking them off.