This is all in Tobias POV. His love for Tris is unending.
His life without Tris. Will he move on? Who will it be? Or will he just never love again?
He knows that Tris is in a better place, but he wishes that Tris is here with him. But that is not possible anymore. Tobias insists that everyone calls him Four now. He doesn't want to be called 'Tobias' anymore, because it reminds him of Tris. His love for Tris will never end. 'Tell Tobias I never wanted to leave him,' haunts him everyday.