Why has mrs manette maintained the fiction for Lucy that her father was dead?

Mrs. Manette maintained the fiction that her husband was dead in order to protect Lucy from the painful truth of his imprisonment in the Bastille for 18 years. She believed this lie was necessary to shield Lucy from the harsh reality of her father's past and to ensure her daughter's happiness and well-being. By keeping this secret, Mrs. Manette hoped to spare Lucy from the emotional burden of knowing the truth about her father's imprisonment.