Survival Island
(aka "Three")
(2005)

Short version:
Jack kills Manuel, and Jennifer is rescued from the island and leaves it without taking Jack with her.

Long version:
On a beautiful island, businessman Jack (Billy Zane), his gorgeous wife Jennifer (Kelly Brook), and "latino stud" staff Manuel (Juan Pablo Di Pace) are the sole survivors of a boat accident. Tensions heat up because Jack thinks that Manuel is after his wife, which is somewhat true although nothing has "happened" yet. After a dispute, Jack tells Manuel that they don't need him. However, Jack is unable to fish anything because he doesn't have any diving mask.

Jack steals the diving mask of Manuel and goes fishing. Manuel wants to go after Jack to kill him, but Jennifer stops him and Manuel takes advantage of the moment to have sex with Jennifer. Jack quickly finds out, and leaves her, and goes into the jungle and manages to survive, and even finds a boat that he repairs.

Jennifer suggests to Manuel that they take the boat and leave on their own, without Jack who has turned into a psycho. However Jack has prepared the boat so that it sinks. Jennifer and Manuel barely manage to return to the island. After several fights with Jack, Manuel dies

After a year, Jennifer is picked up by a boat. She leaves the island without Jack, he notices it too late.

Thanks Tilman!