Afternoon Affair: Rear Window (1972)
1972A chick cheats on her patron with her ex-boyfriend. When he asks her for money, she blackmails a wife who is cheating on her husband into fucking for money.
Actors: Chigusa Takayama
The Key (1974) aka Kagi
1974An elderly college professor wants to bring the joys of sex to his wife. He bribes his son in law to shag her because it makes him jealous and he can perform better. He keeps a journal of his fantasies in a locked cupboard, hence the title, and hopes that his wife will find the key and read it.