North Star (Polaris #1)
M.E. Montgomery

Alex North found himself in the one role he never wanted - guardian of his nephew after his sister and best friend are killed. On unfamiliar territory as a dad, Alex gave up his bachelor lifestyle and worked to create a nurturing environment for five year old Aiden. Attempting to hold his new life together, he masked his pain and threw himself into being the rock for his family.
Brought together by fate on several occasions, Alex decides Mikayla is the key to heal not only Aiden, but himself. He recognizes that only she can offer him the kind of love he never thought he would find. Mikayla discovers she has the strength to give love a second chance as well as the courage to fight for it. Together they heal each other and begin to create a future together.
But not everyone supports them, and outside forces threaten to destroy all the happiness they have worked for. Will Alex and Mikayla be strong enough to hold together the fledgling family they are building? Or will the past and the present work together to rip them apart?