The Last Embrace by Pam Jenoff
August, 1940 :Sixteen-year-old Addie flees fascist Italy to live with her aunt and uncle in Atlantic City, where she finds friendship with the Connally family and their three sons. Spending an idyllic summer with the oldest, Charlie, shows Addie the love she has always been missing. But war changes everything. When one brother’s actions lead to the tragic death of another, the Connally family is devastated and Addie along with them. Now she has no choice but to escape again, this time rebuilding her life in war-torn London.
But, when Charlie reappears in her life, Addie discovers that the past is impossible to outrun.