The Fountain by Emily Grayson

Twenty years ago he'd disappeared without a word, leaving her alone on their wedding day...

Now Will Combray has returned, older, but still handsome and unpredictable, throwing Casey Becket's ordered life into chaos. After his cruel and mysterious disappearance, Casey had turned to her best friend, Michael, the man who knew her as no one else.

Michael had promised to take care of Casey and give her a happy life, and he has kept his word. But now, with Will's sudden return, Casey must find the answer to an impossible question: What and who does she really want? The wild, mercurial passion of Will? Or the comfortable, secure love of Michael?

Tugged in one direction by faithfulness and honor, and in another by pure desire, Casey must look back across the terrain of her life to discover which man will satisfy her heart.