Wife don`t want to come back from parental home

Hi... My marriage in 2014, I have 4 month son, after 3 months of my marriage my mother in laws pressurizes me to leave my parents house and leave separate, to settle the things I leaved separately with my wife at another city, after 9 months again I back to my home for 4 months for official work, where my wife refuse to live at my parents house, and went to her parent house, and refuse to come back, then I went with my family and mediator n her relatives, convince her to get back continue relation then she came and again we went to other city with my wife. during this period we had good news. after 2 month of pregnancy we came to my parent home, after week she went to her parents house when my father went to get back she refuses to come back. again I went to get her back but again she refuses to come back, where my mother in law given condition "If I has to settle at her parents city then after she will continue the relation, also indirectly demands for money" this condition i refused. then again went to get back her, she continues the refusing. while this period she was pregnant so did all check ups and medical facilities as well as all delivery expenditure. after 4 moths of delivery of baby I again went to get her back with family and mediator, again she refuses to come back. she is there about a year. now what should I do..?