Sebastian has been different ever since the whole incident with Anne and uncle Solomon. You were there and for a second Sebastian thought he was done and he’d been sent to Azkaban if you told the ministry, but you loved him too much.

You couldn’t betray him like that and lose another person you loved.

You didn’t tell the ministry, and even though Anne was lost, you were there supporting him every step of the way.

But Sebastian can’t help the pull of dark magic coming back. He couldn’t tell you, not when you two are so happy now..