"I don't need to want anything from you," he says. "I already have it."

He wanted Crowley to serve him, and now he is obedient. As that human politican-philosopher once said back during the Renaissance days, it is better to be feared than loved; there is no doubt in his mind that Crowley fears him. That fear, the dread of pain, will keep him loyal even surer than love.

After all, he loves Aziraphale, and he still brought him to Lucifer when demanded. Fear is a trump card even for celestial beings.