The Hidden Lover.

Kiyoshi Yoshida plays Sotaro, a popular television performer, who manages a one-night stand with country-girl Yuko (Yuko Katagiri). She falls madly in love with him, and he enjoys the home-spun attention. When Yuko agrees to a prenuptial contract demanding her silence about the vows and permitting Sotaro the luxury of an "open marriage," they wed in a secret ceremony. However, after a couple weeks of Sotaro's womanizing, Yuko is unable to handle the situation and she attempts to kill both her husband and herself. The resulting scandal costs Sotaro his reputation and career; Yuko is sentenced to a 3 year jail term. But when she gets released, they get back together and try to establish the marriage on a "firmer footing."