How can I file for a divorce without my partner's consent?

I've been married for 22 years and since the very first year of my marriage I've been beaten and abused by my husband and partially by his family. I shifted with my old mother because I recently lost my father so it was hard for me to live in that atmosphere. I asked my husband for financial support only for my basic needs but he refused. Rather, he started harassing me by posting foul things about me on Facebook and making fake accounts with hideous posts. He's trying to ruin my image in front of my friends through social media. My husband would occasionally call/text me and send me foul messages or threads. I asked him to file for a divorce if he cannot stand me at all but he refused. My children are with my husband because they have their exams and I don't have enough money to help them, but he would even go on harassing and beating my elder daughter because she supports my decision of staying away from him. I want to file for a divorce but I'm scared that it might cost a lot.