She's Not You by Mimi Barbour

Contemporary Romance:

Sick and alone with her three-year-old daughter at Christmastime, Belle Foster needs help. When her neighbor’s brother gets involved, she welcomes the soft-spoken good-looker into her world. Rescuing her kidnapped daughter isn’t part of the deal, but any man willing to babysit his sister’s menagerie of pets and cares that much about a stranger’s baby is a guy she wants to get to know much better.

Jesse has only loved one woman in his life. Years ago, she left him with a broken heart, a crippling dependency and too many poignant memories. No one can replace her. No other woman has ever come close. So why does this loving mom continually sneak into his head? And why can’t he shake her loose? One needy girl in his life, a sister who expects him to live on a pedestal, is enough for any man.