Sorry it's me again, but it's driving me mad! I'm looking for this fic: during an argument Blaine hits Kurt. They are both shocked by that. Kurt waits for Finn outside and Blaine is losing his mind. When Finn arrives he threatens Blaine and leaves with Kurt. The day after, Blaine goes to Dalton's counselor who invites him to join some anger management group. I think Blaine's father used to hit his mother and Blaine promised himself never to be like him.
Eventually, Kurt sees Blaine again.