L'appassionata (1989)

Gilberta is a widow and piano teacher who, all unbeknownst to her, is mostly supported by her 16-year old son, Enzo. He manages this by selling old, forgotten family bric-a-brac and by cleaning the community swimming pool. To improve their circumstances, Gilberta rents one of the rooms in their lodgings to Toni a handsome young man. Toni takes Gilberta to his bed, and she takes him into her heart. Her son warily accepts the arrangement, but is concerned for his mother. These concerns prove justified when the lodger takes up with a (much younger) music student of Gilberta's. Driven literally mad with her grief at this unendurable abandonment, Gilberta is eventually compelled to ask Enzo to help her end her misery.