Divorce from wife for mental harassment.

It was a love marriage. Soon after marriage, incidents heppend that proved that she is very angry and bad-mouthed. Indeed I found her behaviour to be possessive at first but I realized that it was insanity, checking my phone regularly, restricting me to talk to my cousin sisters, any girl texting or calling me creates a chaos in home. Then, she decided to pursue her PhD and got admitted. We share the same home town Jorhat but my job is at Silchar. And being at Silchar she never stayed in my home. 1st 6 months she said she needs to in college hostel but after 6 months she shifted to her home. All these out of no reasons. Even she never needed to make a single cup of tea in my home. But, she is too self centered and very rarely talked to my parents. Finally, due to some official works in another town I met a girl with whom I kept talking after the job was finished. She was very angry to know so. So, I let her talk to the girl and clarify, but she asked me to keep quiet and told the girl that I have told my wife that and the girl are in love and she will do anything to unite us. She tried to trap the girl. A very wicked move. But her trap failed. But a year after this she still blames me that I am having an affair and she went on to say this to all my relatives and colleagues. Even any problem between us she used to share with my male colleagues and even with their wives. Now, on repeated calls she doesn't come back and refuses to give mutual divorce. She wants me to file case against her. Or for mutual divorce she wants 17lakh rupees and 15 thousand per month. But I am a state government employee with net monthly salary of 32 thousand only. What do I do?