Marta of the Lowlands.

Sebastien, a landowner, shelters the orphan Marta in exchange for sexual favors. When, years later, Sebastien's fortunes ebb, he marries Muri, the daughter of a rich man, and arranges for Marta to marry the shepherd Manelich. Sebastien assures Marta that Manelich knows of their relationship and will not interfere, but she discovers that her husband is ignorant of the affair and, in fact, loves her. Because she comes to return her husband's love, she confesses her past, after which Manelich kills Sebastien. With Marta at his side, the shepherd then returns to the hills. -From TCM.com Database, powered by the AFI.