How do you know if you've found the one? Can you really love the one you're with when you can't forget the one who got away?

Emily Giffin, author of the New York Times bestselling novels Something Borrowed, Something Blue, and Baby Proof, poses these questions—and many more—with her highly anticipated, thought-provoking new novel Love the One You're With.

Ellen and Andy's first year of marriage doesn't just seem perfect, it is perfect. There is no question how deep their devotion is, and how naturally they bring out the best in each other. But one fateful afternoon, Ellen runs into Leo for the first time in eight years. Leo, the one who brought out the worst in her. Leo, the one who left her heartbroken with no explanation. Leo, the one she could never quite forget. When his reappearance ignites long-dormant emotions, Ellen begins to question whether the life she's living is the one she's meant to live. At once heartbreaking and funny, Love the One You're With is a tale of lost loves and found fortunes—and will resonate with anyone who has ever wondered what if.