Why has Madame Defarge deliberately excluded her husband for her conference with the Vengeance and Jacques three?
Because his Uncle was responsible for the rape of her sister and the deaths of the rest of her family, Madame Defarge is ruthlessly determined to exterminate St. Evremonde (Charles Darnay) and all his relations. The purpose of her conference with the Vengeance and Jacques three in Book the Third, Chapter 14, is to plot the killings of St. Evremonde's wife and child. Madame Defarge knows that her husband, who has long been associated with St. Evremonde's wife Lucie and especially her father, Dr. Manette, does not share her resolve in this matter, and she is afraid that he may even interfere with her plans. She therefore wants to carry out her murderous schemes quickly and without his knowledge.