Divorce And Child Custody

Sir I got married on 2016 May, i see my wife behavior changed after she went to in laws house during pregnancy we were staying near to laws house before as i was working in Banglore. i was frustrated with there emotional blackmail i left job and moved to other state. Now my baby is 11 months there parents and wife started allegations from the first month that i am not giving money for baby care. Even my wife is earning and she is giving all her money to in laws from day one of my marriage. And everything i was taking care. They have planned such a way that all hospital bills and consultation are paid from my Father in laws and wife card, and i have become fool by giving them money on hand without any proof.Now they are blackmailing me with the message that i sent in frustration and given false statement to all my relatives that i will beat my wife and so on. They are making me more angry in front of others and they act innocent seriously this is kind of mental pressure i am facing. How can i file divorce and get my child custody back they need my child because my wife sis dont have children. It has been more than 6 months i havent seen my child and they wont show for my parents as well.