It happens when Blaine least expects it.
When Sebastian’s at Lacrosse practice and he looks up and sees him waiting in the stands, and his face breaks out in a wide, open smile that Blaine’s never seen before. When they’re at the Lima Bean and Blaine realizes that he can’t memorize his coffee order, because Sebastian gets something different every single time. When Sebastian drives three hours to watch McKinley’s sectionals even though all of Blaine’s friends hate him, and he claps so loudly that the rest of New Directions can only stare.
They don’t fit, they shouldn’t fit, except for the fact that they just do.
“I love you,” he says, in the quiet moments. When Sebastian is dreaming and silent, when Blaine fits right in the crook of his elbow, when he is certain that Sebastian can’t hear him.
But the arm around him tightens, and Sebastian’s lips quirk up in a small, pleased smile, and Blaine knows that he feels exactly the same way.
They shouldn’t fit. But they do.