"
you moved on
It's hard to hear your name when I haven't seen
It hurts to know you're happy. It means that whenever he see her happy, he is hurt because he thinks that what happen to them was just nothing, like nothing really happened. And it hurts that you moved on. It means that he is hurt because he can really see that she already moved on and she is happy even though he's not beside him already. To sum it all, he hasn't moved on and the one she loves HAD already moved on and he is hurt by the way she is expressing it.