Who is Antoinette from Friend of My Youth: Stories and what is their importance?

Antoinette loves Dudley but knows that he has a child with Judy. She attempts to prevent him from seeing Judy and his child whenever she can, and being faced directly with the situation makes her feel physically ill. The reader is given the impression that she would rather ignore Judy and try to forget that part of Dudley's life. The fact that she prevents him from seeing Judy suggests that she knows there is still something between Dudley and Judy, and that she can never be the sole object of his attention and love.