Rich Kids (1979)

Two ultra-precocious Upper West Side 12-year-olds, Franny and Jamie, are best friends. Jamie, the "new boy" in town, has experienced his parents' divorce and guides his friend Franny in the art of surviving her own folks' imminent split. Franny senses the divorce because she has been secretly watching her father arrive home at 5:00 every morning and pathetically try to brush off (to his wife) and hide (from his daughter) the fact that he has been away all night. She is down in the dumps and finds a kindred spirit in her buddy Jamie, whose parents split up long ago. He points out the advantages of being a "child of divorce", and is so persuasive that he almost convinces himself as well as Franny. When Franny convinces her parents to let her go to a sleepover with Jamie, they explore their budding curiosity for the opposite sex. When Franny's mother finds the book "The Joy of Sex" in her daughter's bedroom and discovers that her daughter has deceived her, four frantic "adult" couples converge on the sleepover site--Jamie's father's swanky, fantastical bachelor pad--to catch the two in a compromising position. Ultimately, Jamie and Franny realize that, in order to survive the undeniable disadvantages of their parents' divorces, they must weather the hard times together as friends...if not more.