Turns out that by betting so small he was begging you for a raise on every street...
Too bad you didn't oblige
I would probably raise this flop for value (vs smaller pairs and overcards that could call to see turn: I think we still can get calls from certain villains having stuff like AK-AT, KQ here) and/or for protection against overcards that may come on the turn and improve his hand. But if you called flop, I think it was fine to call these small bets to the river