Need help with getting divorce

Hello, Me and my bf got a Arya Samaj certificate in Delhi in 2013 and started living together in Mumbai. IN these three years, i had to constantly support him financially, and whenever i Asked him to take a job, it would end in worst fights. He has abused me many times verbally, (no physical abuse) and i was stressed to a level, where I had many hormonal and stress issues. His and mine parents are not known to this arrangement we had. Unable to take the pressure, I quit Mumbai and shifted with my brother. My questions are, 1. How can i file for a divorce (which I know i should)? I want to know the grounds. 2. My bf has threatened me not to give divorce, so that I am struck with him. I have proof of his threats on phone and messages. Can I use that in any manner? 3. i DO NOT want to stay with him anymore, because he doesnt treat me well. Can the court force me for the same. 4. What are the legal costs for divorce? Just an idea would help. 5. I dont want any alimony or accusations, but just a divorce. What should be my approach. Thanks