Wanna disown my wife

I got married in the yr 2017 after my first wife's death. I married as my son was 6 and he was missing his mother. I thought that he would get a mother who will take care of him but nothing happened like that. First i thought to keep them in Kolkata along with my son and I did that however that was a bad decision. I asked her several time to come to Hyderabad but everytime she denied stating that she will miss her friends, she can not be a full time house maker, she wants to do job etc etc. My son was also not doing well. His education, his behaviour all started to change. His health started to deteriorated. He was not getting proper care. In last nov i got my son back to Hyderabad and then i came to know that he was not happy with her as she used to treat him bad. She used to bit him and was also not taking any care of him. Today i am sending her 15,000 every month. I have my own expenses. I am clearing my loans, for which the emi is 20,000/month. My sons education, my rent and food etc. I am not able to carry this burden. My purpose of marriage is not fulfilled and i hv welcomed a disaster. I want to get rid of this. Please help. I want a mutual seperation/divorce where I sudn't have to pay much if she ask fr alimony however i do not want to give her any money .