short story the Rememberer

She is talking about how her lover was a human that turned into animals. The short story describes how he turned from one into another. She talks about her days when he was a human. Describing the details of what happened to him. She says he is "experiencing reverse evolution". He is going from human to other animals. Evolution is basically evolving from animals and turning into humans. This short story fiction is interesting for the style that it's written. I was not expecting to have a reverse evolution story.