Movie about a real-life cuckold situation (kind of)

On Netflix currently they are showing a documentary called "The Galapagos Affair--Satan Came to Eden" which is the story of m u r d e r on a remote island of the Galapagos way back in the 1930's. It is a good watch regardless, but the best part of the story is the obvious cuckold relationship involved. Only two families live on this otherwise deserted island about 60 miles from the nearest inhabited island, when a woman, claiming to be a baroness from France, comes to stay with two companions, a skinny, pale man who is her husband, and a more fit, well-tanned man who they say is the Baroness's assistant. Over time it becomes clear that she is involved romantically (i.e., is fucking) the assistant, and spends all her time with him, while the husband basically becomes their servant, doing all the menial chores. My dick just twitched writing that last sentence. What is neat about the movie is that, before the m u r d e r s, these people were fairly famous (the newspapers loved a story of people leaving civilization to find paradise) so there is a lot of film footage of the couples on this island..plus clips of the Baroness in a revealing outfit in a movie a visiting ship captain made. Cool.