What to do, to save my 12 yrs old married life?

I m 38 years old good looking man with my own business.We married 12 years back.My problem is my in laws who always misguide my wife and interfere in our personal life.Even many times they insulted me and and my parents in a big way as because my one bro in law is police officer.My wife abused and insulted my mother,my married sisters and beat our two child,even she slapped 32 in a single instance to my 11 yrs. son.I am the only son & can't live separate to my parents as they are chronic patients of heart,diabetics,multiple arthritis etc.mentioning also that I am post graduate while my wife is just 10+2 & no interest in further education,our children are going in best schools of city.She spend her maximum time with either in planning to insult ourselves on the phone with my in laws or in looking at TV for new idea with different serials.Now I broken all the relations with my in laws but never compel her to do the same.But she is trying regularly to maintain relations with them and coarsening me by beating children, imposing false allegation on us, spreading false news about us in society and breaking our close blood & social relations through bad behavior.I don't want to leave her for the sake of my children,but feeling difficult to live with her.please suggest me,what to do??