Roxanne, the Odyssey of Sex (1976)

The blissful newlyweds, Roxanne and Eddie, arrive on a private island belonging to Nikolas, an unethical and unscrupulous shipowner and the groom's wheelchair-using father. Before long, Nikolas demands an heir; however, an old psychological wound has rendered Eddie incapable of fulfilling his marital duty and Roxanne's sexual needs. Now, Nikolas is determined to use every trick in the book, including strong-arm tactics by his loyal henchmen, to get what he wants. Can the couple oppose the disturbed man's will?