Between Bodies Lie — H.M. Blanc

Attempting to flee his declining literary career and failing relationship, Cristobal Porter travels to an island in the tropics to research his latest novel. There he meets Ana Kaplan, the wife of an American diplomat and is immediately drawn to her by what he perceives as the shared depth of their loneliness. When Porter's young mistress arrives on the island and enters into an affair with Ana's husband, it is the catalyst that draws Ana and Porter closer together.