Two families, usually from vastly different social classes and lifestyles, swap wives/mothers (and sometimes husbands) for two weeks. In fact, the programme will usually deliberately swap wives with extreme, polar opposite lifestyles, such as a dramatically messy wife swapping with a fastidiously neat one. Despite using a phrase from the swinging lifestyle, couples participating in the show do not share a bed with the "swapped" spouse while "swapping" homes.

Source: Wikipedia.org