Valmont (1989) online

Set in Baroque France, a scheming widow and her lover make a bet regarding the corruption of a recently married woman. The lover, Valmont, bets that he can seduce her, even though she is an honorable woman. If he wins, he can have his lover to do as he will. However, in the process of seducing the married woman, Valmont falls in love. Based on the same novel as "Dangerous Liaisons."