Why are Marcos and his wife separated in the novel, Tender Is the Flesh?

At the novel’s start, Marcos is living in his “fairly isolated” country home by himself (27). Not long prior to the narrative present, Marcos’s son Leo died in his sleep. Because Leo was young and because Marcos was the one who “tucked him in,” Marcos is plagued by guilt and grief (72). His wife Cecilia has been similarly incapable of healing from her sorrow, and has thus “gone to live with her mother” (5).