She worried about that mirror of his.
She might be worried because it makes him self-absorbed. By looking at the mirror he would notice he imperfections, his 'apeness', and he would try to fix it. Of course he can't fix it because it is in human nature to be ape-like. She is probably worried about him because the mirror is probably also making him unhappy, which she would not like. The mirror is also probably changing his focus. He is no longer looking at her, which makes her sad, but that's the cost of having a mirror in your house grl. She wants him to turn back like he was before the mirror ' face settle back once more into the gentle lines she had once known. '