Moon Over Montego Bay (Moon Series #1)
Jane Graves

When Nick met Sarah, it was love at first sight, and he was convinced she was his soul mate. When he woke one morning to discover she'd disappeared without a trace, he was devastated, but not nearly as upset as he is a year later to discover that his estranged brother is getting married. To Sarah. In three days.
There's only one thing Nick can do. He hops a plane to Montego Bay, determined to convince Sarah that his arrogant, obnoxious brother isn't the right man for her--and he is!