Change of name of my son

Sir On the birth of my son me &my wife selected a few names and the name opted by my wife was a long one (Nakshatra) and i thought it would be difficult for our son to speak when he is young. So I finally put his name as Netik in Birth certificate. Now she do not even utter his word and keeps me reminding that she won't call him by this name ever &says that only mothers have right to select name. I requested her parents to make her understand but they never help me in it. Her parents not even support and brings any solution even we have any disputes between us and always ask her to come at their house. Recently she stayed at her parents house and spoke nothing for 5 continuous months.It was only me who initiated to talk,and such instances have happened several time but for shorter durations. She also keeps me threatening to suicide and file police complaints if i don't accept her things. I want your advise what to do, and if I have to change son's name then how can it be done. Our son is 2 years 8 months old. Regards Gaurav