Secret of a husband (1965)

Lawyer Fan Kam-man believes that his wife Chun Yuen-yung perished in a plane crash three years ago and walks down the aisle again with Yan Bik-kei. In fact, Chun survived a crash-landing on a deserted island with fellow passenger Wong Ah-lik, a biologist. Returning to civilisation, Chun sabotages their wedding night at the hotel. Overjoyed with her safe return, Fan pulls off a feat with his mother and wife to terrify Yan into divorcing him. However the lie is exposed when Wong shows up. Unyielding, the women settle to serve as wives to the same man. Mistaking Fan for the person Chun is going to see, the eavesdropping Yan goes to the date in her stead and unwittingly sleeps with Wong. Yan finally settles for Wong, putting an end to the topsy-turvy.