The Promise of Christmas by Tara Taylor Quinn

Leslie Sanderson's brother, Cal, is dead--and he's left behind two children no one knew he had. She and Kip Webster, Cal's closest friend, "inherit" these secret kids.

As they form their makeshift family, Leslie and Kip decide to share a house. And that leads to other kinds of sharing.... One night, just before Christmas, Leslie tells him about the devastating thing that happened when she was young--something she's kept secret all this time.

Because in Kip, she finds the promise of safety, acceptance and love. The promise of what family should be.