The truth is this:
The Wii gets purchased for the family with Wii sports and Wii play for the other game. The husband gets all excited and spends all his time with the machine and not with his wife, so she quietly takes one of the controllers into the bedroom to keep herself company and the husband doesn't notice since hes busy playing single player anyway.
Eventually the relationship starts to change with the wife getting herself in shape with Wii Fit to make herself more attractive to her man and or failing that find a new man and the husband moves onto Mario Kart and plays that incessantly. Eventually arguments ensue and they buy a 2nd Wii for the house so they can both play.
This explains why Wii Fit and Mario Kart sell so well and why they sell so many systems.
Tease.
