My wife was already married during my marriage

I got married in 2010 arrange marriage with proper marriage ceremony ... After marriage only my wife started touching me and bcoz of that I hav to separated from my family... Her every day demand for gold jewellery, flat, car etc. Made my life like a hell... From this wed lock I hav 2 daughters.... But her toucher was extremely unavailable... She left my home in aug 2018 and file a dv case in Jan 2019... In Jan I came to know that she had done 2 marriages b4 me.... She done 1st marriage in 2000 and in 2002 she left her matrimony house and file complaint against his husband and family 498 a, maintenance etc., But in 2004 they done notry divorce in front of notry office... And their case closed in 2006 ...she done one more marriage in 2004 but I don't hav proof of that marriage... I hav her case paper which I arranged from court in that it is maintained that she done notry divorce with first husband.... What shod I do now... I am ready to take my both daughters custody... Can my marriage is null and void .... How should I reply her dv case and recently she filed 498a also against me and my family.... Kindly help me