So Long Letty (1920)

Harry Miller is a "natural-born mixer" while his wife Grace is a homebody, distressed by her husband's errant ways. Grace finds a kindred spirit in Tommy Robbins, who lives in an adjoining bungalow and whose wife Letty is devoted to the cabarets. Harry admires Letty as much as Tommy admires Grace, and suggests to his neighbor that they arrange an exchange of wives. The wives overhear their husbands' plotting to obtain divorces and, still in love with the men they married, conceive a counter-plan of a week of platonic trial marriages. Over the seven-day period, the wives make life so miserable for each other's husbands that the two men gladly return to their respective spouses.