O Medo (1954)

Irene Wagner, the wife of the prominent German scientist Professor Albert Wagner, had been having an affair with Erich Baumann. She does not disclose this to her husband, hoping to preserve his innocence and their "perfect marriage". This fills her with anxiety and guilt. However, Johanna Schultze, Erich's jealous ex-girlfriend, learns about the affair and begins to blackmail Irene, turning Irene's psychological torture into a harsh reality.