Lian Yu did not break him.
Nanda Parbat did not break him.

Sara Lance will. Does. Every time. Turning his thoughts from blood and vengeance to protecting her family in Starling, to finding a way off the island in order for her to stay in Paradise where she belongs. So Oliver moves, reaching out to draw her into his arms. To kiss her forehead gently.

"Monsters don't belong in paradise, Sara. I can't stay, I can't bring what I am to a place like this."