Crazy Desire (1962) on Netflix

Plot summary

Antonio Berlinghieri is separated from his wife, keeps a lover, and has a son in a boarding school in Pisa, where he is driving one summer in his sports car. On the highway he comes upon a group of teenagers whose car has broken down and stops to help them. Their frivolous attitude puts him off, and he thinks about driving on, but then he notices Francesca, fifteen, and decides to stay with the group and try to seduce or marry her despite the difference in age. He joins their party and foots most of the bill, drawn to a girl who seems his complete opposite.