Mental Harrassment

I am a woma aged 53, married for 30 years. I come from a respectable family married into a respectable family of business owners. My trouble has been my mother in law who has mistreated me sincethe very beginning of my marriage. Her area of expertise being taunts,throwing tantrums, asking me to accomplish impossible household jobs and other errands and endlessly cause mental trauma. My husband has been equally mistreated by his parents. I never had the courage to stand up for myself nor did my husband ever stood by me when he saw everything actually happening to me, asking me to ignore her. I have never ever spoken about my mistreatment and mental and emotional abuse at the hands of my mother in law to anyone not even to my parents. Lately I have caught her lying aboyt me to her family, casting aspersions and what not. The latest has been an accusation of theft of her cell phones which she apparently dropped somewhere. I am a CFO in a reputed company yet this is my situation only for lacking courage and for the stupid notion of what would people think/ say! I cannot take it anymore and i feel that I desrve justice and that she should receive some punishment for years of my mental emotional and physical abuse, Hope someone can help me.