You have to address such issues intellectually, not emotionally. When your husband is not realising, there is no fun in complaining. Stop complaining about your mother in law. When you over hear her complaining about you, you go to her, look in her eyes and just give smile. She will be embarrassed. She may try to conceal her embarrassment by showing her anger or some reaction but do not bother about it. Only such embarrassment can stop her doing this activity.