The Duchess at the Butler’s Mercy

Duchess Ines, married to the Duke of Edward, a man more affectionate than anyone else. However, Ines harbors a secret she cannot tell. It is that she is more aroused by men who would humiliate her than by affectionate men. When her butler Leon learns this secret, he begins to abuse Ines to his heart's content while the Duke sleeps... (Source: Naver Series, translated)