An Ordinary Drowning - Book One of The Mermaid's Pendant by LeAnn Neal Reilly

John Wilkerson wants a timeout from his life, and a week on a Caribbean island without his girlfriend Zoe sounds perfect. And it is, at least until he almost drowns -- only to be saved by a mysterious woman. After that, John's spring break turns into something much longer as he tries to figure out if the appealing young woman named Tamarind holds the key to his future. Over the course of one hot hurricane season, both John and Tamarind will learn that their romance is no fairy tale.