The Thorn Birds by Colleen McCullough

Sometimes when he didn’t know he was being watched Meggie would look at him and try desperately to imprint his face upon her brain’s core . . . And he would turn to find her watching him, a look in his eyes of haunted grief, a doomed look. She understood the implicit message, or thought she did; he must go, back to the Church and his duties. Never again with the same spirit, perhaps, but more able to serve. For only those who have slipped and fallen know the vicissitudes of the way . . .