Office Lady at Night: Tongue Licking (1981)

A wife working as an office lady is raped. Her husband tries to see her as a victim, but he can't accept that another man has touched his wife's body, so he cheats on her with a girl he meets in town. The girl is what you would call promiscuous, having sex with any man who approaches her, and is even comfortable with a foursome with her friends. The husband's preconceived notions about sex begin to crumble. Meanwhile, the wife, perhaps having gotten over the rape, begins cheating with one stranger after another. The wife's preconceived notions about sex also begin to crumble...