I know that most will say that it is terrible that Tobious and Christina fall in love but I think it is one of the best ways to end the story. Tobious and Christiana can't just nope around. They are young and have a life to live. They deserve to be happy and are held together by Tris. Tris is the bridge between them. Tris will always have a place in their hearts no matter what. The Divergent story had to end somehow and if it has to be with Christina and Tobious falling in love then so be it. I think that Tris would be happy for them.