Women are the keepers of the seen and the unseen in the family. Things between husband and wife should stay between husband and wife. We are one another’s representation. (If abuse is happening one should only tell a person who can actually help and interfere.) Backbiting is a major sin in Islam in general & backbiting against the husband is even worse, because with that the women are hurting a right of the husband he has in that marriage. So no, it’s not permissible at all.