How to file a divorce

I had completed 1.5 years of my marraige. We have lot of fights in the first year even sometime it turned to physical.My wife has very different thought process. i am from middle class joint family background,she is from delhi necluear family background. she uses a very rough language( abusing my mother,sister) in talking & Quarelling which sometime end with physical contact.On every quarell she never gives up even i try to get out the room she will start keep quarelling & at end she will use abusive language. I tried many times to make her understand & live with peace with her but invain. I have spent 75 thousand on her just 15 thousandon my family & 35 thousand on the marriage debt for which she always quarrels & blackmail me . Later her family jumped in my home threaten me to take my wife away from me & force me to write down a letter where i agree i have physical fight with my wife. Point is fights were many times from her side or mine...she also went physical many times & i remain quiet.....but i never complained any body..even i have scars on my face made by her.... My wife wants me to leave my family & live like puppet in her hand,my mother who spent all her money which she got when my father died in my marraige & more which is as a debt to us....my wife wants that i should not help my family...now they always threat me with the letter if i disagree to any of their terms........even they had come to my place to threaten me with their contacts in high officials... my wife starting abusing my mom on her face.She misbehave with her like taking away food from her hand,not allowing to see tv or cook,not allowing her talk to many society woman.My mom stays in her room from morning to night just comes out when time to eatI am not even allowed to talk to my mother in home or by phone...if i found talking she i have to face my wife quarelling words & many other things......i am on the verge to commit suicide many a times.......But i have an old mother so i cannot do so & she is quiet beacause of me. In the mean while she got pregnant 4 month back.........the letter they took from me is 6 month old......even after that letter written i have never lifted hand on my wife but she had done it thrice....& continiously indirectly her family is blackmailing me...even they had abused me for 4 days in my own home & pushed me & harrashed me.... My wife is about to have a baby after more 5 months so i don,t want to stand back now for divorce or any fight against what they did bacause that will affect her health & the chld's health.... since my life has become hell..... can somebody tell me what max will happen if i file a divorce case in this senario. after the birth of the child....I am ready to take the child responsibility......but they will make this child also as a weapon against me.What max can happen to me because its better to die one time than everyday......