Forever and a day - Jill Shalvis

Grace had a great life in New York, until it shattered.
Finding out at age 30 that you're adopted will do that to a person.
With everything she once believed in yanked out from beneath her feet, Grace travels across the country to find herself.
She goes looking for roots, but what she finds is much, much more.
Some of that comes in the form of Dr. Josh Scott, an ER doc working nights.
He's tough and jaded when Grace first shows up at his place looking for his employee - whom she believes is her birth mother.
But she's wrong. And exhausted or not, Josh is
protective of what's his: his young son, his staff, his quiet world.
But even his own defenses are no match for what he sees in Grace ... a kindred soul.