The Heart Is a Dark Forest (2007)

This drama deals with a woman, whose life is destroyed when she discovers that her husband has another family. Marie and Thomas, both musicians before their marriage, are an apparently happy couple, living together with their two children. One day, Thomas forgets his violin at home, so Marie follows him to bring him the instrument, but learns that he lives in another house with another woman and their son. Thus, she wants to know more about her husband's second life, which marks the end of her old life...