Fighting and defending Maintenance case and Domestic Vi

I am a Central Govt. servant posted in Guwahati. I got married on 30.11.2011 at Kolkata. My wife has filed a false case u/s 498A against me and my parents at Guwahati (our last place of staying together and my paternal house) on 18.06.2016. Thereafter, I filed a case seeking divorce at Family Court, Guwahati on the grounds of mental cruelty on 24.06.2016. She went to her paternal home at Kanpur (U.P) and filed a case of Domestic Violence there against me and my old parents. She, further filed another two cases of RCR and maintenance, later being the latest. All the aforementioned cases are still pending. I am expecting an ex-party judgement in the Divorce case, since she has never appeared for filing written submissions since the last two years. I have a 5 year old son who is staying with his mother. Pls advice how to fight the case of maintenance? It is pertinent to mention here that I have collected some Facebook and WhatsApp SEX-CHATS that has taken place between my wife and some other person, not know to me. Even, she has shared her semi nude pics with the person. These s*x-chattings and photos sharing took place after she went to her paternal place at Kanpur. Moreover, she has had the history of leaving our home at Guwahati without anyone's knowledge and moving to Mumbai on 46th day of our marriage for reasons better known to her for which a missing complaint was lodged at Jalukbari P.S in Guwahati and she was later detained from train at New Jalpaiguri Station by RPF while going to Mumbai. It may also be mentioned that Police has submitted Final Report in the 498A case and the case is pending before the Honourable Court. Please through light whether these evidences will help me in fighting the maintenance case? I am very much concerned about my son whose life, I think will be destroyed if he stays with his mother. Pls advice.