Where Rainbows End by Cecelia Ahern

Rosie and Alex are destined for each other and everyone seems to know it but them. Best friends since childhood, they separate as teenagers when Alex and his family relocate from Dublin to Boston. Like two ships always passing in the night, Rosie and Alex stay friends, and though years pass and weddings, funerals, and baptisms take place, the two remain firmly attached via e-mails and letters. Heartbroken, they learn to live without each other. But destiny is a funny thing, and in this novel of several missed opportunities, Rosie and Alex learn that fate isn't done with them quite yet.