Friends Will Be Friends (1989)

Carlín is a Casanova kind of guy on his thirties, living on his own, on a flat he rented to a girl friend of his. He frequents women on a promiscuous fashion, while making a living working with his father. His life will take a turn when, unexpectedly, finds himself sharing the flat with the 18-year-old son of his friend, who has no other place to live.