The Little Hut(1957)

A neglected wife is shipwrecked on a desert island with her husband and her would-be lover.

Sir Philip Ashlow (Stewart Granger), his neglected wife, Lady Ashlow (Ava Gardner) and his best friend Henry Brittingham-Brett (David Niven) are shipwrecked on a desert island. This potential ménage à trois where the two men compete for the lady's attention is interrupted by the unexpected arrival of a fourth inhabitant of the island.