Diary of Beloved Wife: Devoted Wife (2006)

Oda is a cowardly and boring man, his only redeeming feature being his diligence. He continues to live with his wife, Ayane, but they can't seem to produce children and are troubled as to whether their relationship will survive. One evening Oda returns home to find a pair of blue toy handcuffs hanging on the doorknocker. Using them, Oda humiliates Ayane. Although bewildered at first, Ayane begins to respond, and Oda becomes increasing excited as he sexually assaults her. In truth, the blue handcuffs were Ayane's contrivance. There was a time in the past when she used to reach climax...