Yeah, I think it takes until this moment for G to fully understand D's feelings towards the Pup, because obviously he knows that D loves the Puppy, but he never thought that he would be /in love/ with the Puppy the same way that he's in love with him. D doesn't try to do anything to hurt G, but he has to pull away from him a little bit as he tries fixing things with the Puppy, and G doesn't think he's ever seen D cry as much as he does every day that the Puppy doesn't trust him. He's never seen him at his worst emotional point in his life and knowing how hurt he is, and /feeling/ how hurt he is just makes G feel like absolute garbage. And in the end, it's G's doing that helps mend the broken path between them. Collectively, they all need each other and it's the realization of that.