One True Loves by Taylor Jenkins Reid
In One True Loves, we meet Emma, whose high-school-sweetheart husband, Jesse, is tragically killed on their one-year wedding anniversary. She doesn't know how she'll go on or if she'll ever find happiness again. Emma picks up the pieces, eventually finding love with her old friend Sam. But then, the unthinkable happens: Jesse is found. Can you have more than one true love?