Mental Harassment leading to get a Divorce

I (am handicapped person) got married to my wife in February 2015. After few days, we have to come my state with my wife, so as to join my job. The problem started from there itself, as her sister and brother-in law were taking care of her and she was not having her mother and father. Her sister complained that, we havent invited them to giving a send off till railway station, but my parents asked them to come to station. They haven't spoke to me for 02 months due to this. While I come out to office, my wife will make a call to her and take advice from her elder sister. Many a times she delete the chat messages being spoken to her best male friend. I also knows him and asked my wife, why she delete the chat messages. She wont give any answer to that. I think I havent told you that, the first night she brought some sleeping pills with her and later in 5 days I said to my wifes' elder sister but she wont be having any sleeping pills with her, my wife showed me the sleeping pills that she was about to throw. She got some sort of fear i thought but I loved her very much. Small small issues now grown up. and in december 2015, she gave birth to a baby boy. Her sister interrupted my personal life and later again fought with me and my family in the hospital itself. After discharge from hospital, I came back to my state as I am a Central Govt. Employee. My wife never made a call to me and never put an effort so that I may hear my baby's voice. She listens to what her sister advices her to do. Its now the fifth month and I am fed up with her argumentations and silly demands. as I am handicapped, her sister said that several times that I am handicapped and now i am in a state of mental harrassment. She was a working lady before marriage, pl suggest me with appropriate law to get my baby. I want a divorce in this case. and what is the procedure of filing a case against her elder sister.?