Jupiter's feed

So if Dietrich is alive, does that mean both him and Wilhelm faked his death…??? You would think he would go back to Reinhardt and show her that he lived, but why did he decide to just secretly live in peace. My first thought was that Wilhelm did something while him and Dietrich were away, and knew 100% that he was alive but kept it from the FL because of his obsession with her. I guessed he was afraid of her leaving him for Dietrich, but if there is nothing wrong with Dietrich, how did he just go along with it?