I'm married and i have a girlfriend who wants to marry me, I'm Muslim

Sir, recently i have be friends with on girl from my professional life, i.e from office, we got close and we were friends in beginning however I am married and i have one kid, me and my coworker we love each other, my coworker said she is interested in getting married to me and be my second wife and she is okay with accepting my wife and my kid, her only demand is, i should give her equal right as my first wife, now my question is, in past before i got married i have face few legal issue with my ex, my ex gf use to fight with me often and i wanted to end relationships so she threatened me to file a case and eventually in the end she did, later the judge dismissed that case because judge was convinced with my proofs. My question is, i want to avoid all this drama again from another girl, is there any bond in our law that i can make my coworker sign, mentioned that she is with her concern is with me happily in relationship and she accepts my wife and my child? Is there any bond or agreement in India? I just want to know because, i want to avoid all the drama that have happened in past, incase if this coworker also tries to file a case on me, i be on safer side. Please let me Note: she is ready to get married to me with her concern, and she said she will make her all family convince.