Almost There
He had found the letters I thought were safely hidden.
He had watched my face and read the fear I thought I was concealing.
Children see far more than we imagine, and my son had seen everything, and the wall I had built to keep the fear from him had kept nothing from him at all.
It had only kept me from knowing that he knew, which meant it had only served to leave him alone with it.
My protection had protected no one.