Divorce

My marriage held on 16th may 2015. After 15 days of my marriage I got my wife was 52 days pregnant. Its cause was her brother-in-law. My parents and relatives told me to take her out. But I thought to take her chance. I made one agreement infront of her brother and mother that she will live happily with me and my parents and she will not make old relation again physically or by phones and she will go to her parents with me with my sweet will because her parents and her brother-in-law is now good relation.And she agreed to abortion to that child. But now she is not obeying to me and always going to her parents house and staying there, her brother-in-law is also coming there she is also making relation with him by phone but physically I am not sure her parents is also allowing to her. She is not coming to my house since last 6 months. I am feeling mentally torture I want divorce what I will do. I am poor family. I am getting 35000 per month in indian railway and she is also a contractual teacher she is getting 6500 per month under government of odisha. I want divorce and what will be my maintenance to paid please give me suggestion what I will do