Why does Lionel Barrett's wife accompany him to Hell House in the book, Hell House?

Barrett's wife, Edith, is emotionally fragile. She finds it extremely difficult, if not nearly impossible, to be away from Lionel for any extended length of time. Though he is unaware that she nearly suffered a total break the last time they were apart, they both know that the consequences might be serious if she did not go along with him this time.