Marriage done by cheating

Hi sir My marriage done in 22 July 2018. My wife and her whole family didn't tell us that my wife had daughter already in live in relationship with someone. Now 2.5 years over and I have son (1yr old). Someone in their city told that your wife has cheated you by miss representing her previous borned daughter belongs to someone. I went to zonal office and applied Birth certificate came to know that her daughter has two birth certificate one is original with my wife name and her boyfriend as parents and another birth certificate shows my wife's uncle and Aunty is parants. I applied RTI to provide supporting documents to both certificates then zonal office provided supporting document that the baby belongs to my wife for another birth certificate zonal given in written no information available. Please let me know is it possible to apply nullity for marriage? 2.5 years happened for marriage and have 1yr old boy baby Now. The day when I came to know truth my wife left me and staying with her parants.