Whimsical behaviour of my husband towards me and my children.

I am a married working woman in a private school. I have two children; elder is in first year engg and younger is in school. My husband works in central govt. Its an arrange marriage of 20 years. Had a separation in 2009 for 1 yr due to beating, humiliation,from husband and in laws. he had also beaten my father on road claiming that he does not allow my children to meet with him. reality was just the reverse. I was pregnant and he had almost abandoned me saying that my parents interference is causing troubles in this marriage. I went back after my daughter's birth when he came to take me because of his pressure, defamation for my parents and still his claim that he loves me. 11 years passed, i reestablished my family with love and care keeping as least dependency on him as possible and tried to do everything what he wanted like not keeping relations with my parents for 5 years. due to his mother's call to my parents to start afresh, relations started. seemed like all is in place. but since last 3 years, my husband's whimsical behaviour towards me, kids and my parents has shot up again. this time, he targeted my son by beating him, cursing him, threatening him not to give financial help if he keeps any contacts with my parents. I had to again leave home and I am at my mother's place since one year. mother in law says, this time he won't come to take you. come on your own. again same defamation, threats and same claim that he loves me and children. I insisted on reconciliing on some written terms to which he has totally abondoned me as well as kids. he occasionally comes, calls, threatnens, abuses and creates scenes in front of my house or daughter's class. claims to destroy me, punish me and family for playing games with him. I am so much depressed due to his successful lies in family relatives, I do not find confidence in fighting or doing anything against him. Please help and guide. NC registered in police station 3 times. But they say, if we register a crime, he may loose his job. Don't know where to start from