The Knot (2010)

Original title: 結び目

You can never wash away the past.

Ayako (Akazawa), a housewife who spends her days nursing her father-in-law and taking care of her husband, bumps into her former lover Keisuke (Ueda Koichi), who is now married and has became a cleaner. When Ayako was a junior high school student fourteen years ago, she was involved in a forbidden love affair with Keisuke who had been a teacher at the time.