Yariman(2008)

Original title: や・り・ま・ん

Kenichi, who had fallen into a rut with his long-term girlfriend Miki, was no longer able to get an erection during sex. One day, Kenichi unexpectedly reunites with his high school sweetheart, Yoshiko, and invites her back to his apartment. There, he makes love to her for the first time in 12 years, even though she is a married woman...