Can I being Husband take divorce

I have been married since Feb 2013. After marraige I was in Dibrugarh where all was ok. On 2013 she lost her mother and on 2014 she lost her father. on 2014 I lost my job and started my bussiness there and due to loss in business I came back home in Kolkata on June 2016. After that I was jobless and my wife got a job in a school. From that time after getting her job She started cursing me and my family and always wants to take me away from my parents. telling lies against my parents so that I go against them. Her support was her Maternal uncles family and they are politically strong. now and then she goes to her maternal uncles family telling lies in my home that she have work in school. On 2017 March I got a job in school in patna. There being frustated with my wife I came into relation with a girl. on August 2017 I came back home again left the job in patna. on sept 2017. The girl from Patna came to me in kolkata and started staying in PG. I again became jobless. In October 2017 My wife gave birth to a child. On Feb 2018 I got a job in chattisgarh and went there with the Girl. She started staying with me. But afterward realising that this is not good again I came back home on June 2018 and the girl went back to Patna again. I told my wife that lets start again freshly. But she is continuing her old things continuously. Her maternal brother threats me over phone to kill me. She threats me to file a 498 case against me and my family. I am helpless and wants to get rid of this woman. But I dare to lose my child. Recently she was admitted to hospital due to cardiac problem. Still she threats me over phone and messeges. Can I file a Divorce and if then in Which ground? Please help.