Typically, if your husband cheats on you in Tokyo and you sue his mistress, you'll be awarded damages from said mistress. It's considered a way of protecting marriage, the Japan Times reports, but last year the Tokyo District Court broke with the practice—big time. A wife who sued a nightclub hostess over a seven-year affair with her husband was denied compensation, because, the court explained, the hostess was simply doing what was best for business in her attempts to retain the husband, a company president, as a customer of the club. It's a "commonly-known" practice, the judge explained, according to the Asahi Shimbun. The April 2014 ruling is making headlines now because judicial experts discuss it in the current edition of a Japanese legal magazine.
And they discuss it rather amusingly, considering the concept of "makura eigyo" technically translates to something like "pillow sales tactic." It's used to refer to a hostess having an affair with a customer so he'll remain a customer. As the experts note in the magazine, this is the first case to discuss whether makura eigyo is a legitimate business practice—and, indeed, they say, the court's ruling appears to set a precedent that adultery is acceptable as long as the "other woman" (or man) is engaging in it for business reasons. If it sounds somewhat akin to prostitution, you're not entirely off-base; the judge in the case compared the club hostess to a prostitute and noted that such transactions do not "damage peaceful married life."