All This, and Heaven Too (1940)

When lovely, virtuous governess Henriette Deluzy comes to educate the children of the debonair Duc de Praslin, a royal subject to King Louis-Philippe and the husband of the volatile, obsessive Duchesse de Praslin, she instantly incurs the wrath of her mistress, who is insanely jealous of anyone who comes near her estranged husband. Though she saves the duchess's little son from a near-death illness and endears herself to all the children, the vengeful duchess dismisses her. Meanwhile, the attraction between the duke and Henriette continues to grow, eventually leading to tragedy.