Regarding Child Custody

I have been married since 12 years ago on 2002 through court registry happily enjoying the married life.after 03 years of marriage i have left my own house and stayed separately.after 2 years my father in laws allot his own flat to stay on that.we were staying on the flat since 2005.i have a son on 2007.during these 12 years i have been work in so many firms privately but from april 2014 i have been jobless and desperately looking for a job.then i have arranged a job somehow to my wife and she is working since aug 2014.due to the job prospects of wife and myself wandering mostly outside of home my son use to stay at my in laws home since sep 2014.suddenly my wife take a decision of divorce as i t seems she was pressurized by her parents..i was stunned at that time and i was totally clueless at the they are not allowing me to take my son even they do not permit me to meet him any how...when i ask for my son to meet they continuously denying to do so even she put a case of domestic violence against me in a ladies cell in local police station.i am in deep trouble so please help me how could i get back my son and what are advantages of father during the child custody.