En Altamar (2018)

Samuel and Isabel who has lost a baby recently have a sexless marriage. She is a heiress of a big wealth and he is managing her company. After celebrating his birthday, Samuel and Mónica, his seductress sister in-law who is married to Carlos sail to a small uninhabited island. But his boat is damaged. They manage to be rescued without anyone noticing that they were doing infidelities. But now the main concern of the couple is to get out of there so that his wife does not find out about their journey together.