The Swallow's Nest by Emilie Richards

In this heartwarming novel of marriage, motherhood, and forgiveness, three women fight for the chance to raise the child they've all come to love.
After a challenging year of seeing her husband Graham through cancer treatment, lifestyle blogger Lilia Swallow is ready to celebrate his recovery. But just as their festive party gets underway, a mysterious guest presents Lilia with a beautiful baby boy, and vanishes.
Toby is Graham's darkest secret-the son he conceived in a moment of despair. Lilia is shocked by Graham's betrayal, but even more surprised by the love she feels for his child. Once abandoned, Toby is now desperately wanted by three women: Lilia, who takes him into her home and heart; Marina, who bore him and now regrets giving him up; and Ellen, who sees in him a chance to correct the mistakes she made with her own son, Toby's father.
A custody battle begins, and each would-be mother must examine her heart, confront her choices and weigh her dreams against the fate of one vulnerable little boy. Each woman will redefine family, belonging and love-and the results will alter the course of not only their lives, but also the lives of everyone they care for.