Four Years.

It's been four years since he saw you last. The last time he saw you, you shoved Hange out of the way when the Cart Titan barreled through to get Reiner. One moment you were there. The next? Gone.

He thought you were dead. Shiganshina killed nearly everyone, and he just had to own up to that. He moved on. Or at least tried to. Until after Liberio, where you were extracted with Eren, and the scouts discovered you were kept as a prisoner in Marley for four years in a cell.