There's a Girl in My Soup (1970)

Synopsis
The television host of a popular cooking show, Robert Danvers (Peter Sellers) has a real penchant for women. After one episode, he finds Marion (Goldie Hawn) changing from a wedding dress to street clothes. Instantly deciding to get to her and "take over" before the groom, Jimmy (Nicky Henson) has another opportunity, Robert invites her to his bachelor pad, a specially designed command center for his romantic adventures. He turns on the English gentleman's charm, only to have Marion laugh and suggest forthright that they sleep together. She moves in the following day and the two vacation in France on the Riviera and tour the wine country before returning to London. Upon their return, Robert proposes to %Marion; she rejects him in favor of Jimmy, however, who has sworn faithfulness to her and given up cheating forever. ~ Dan Pavlides, All Movie Guide