Question Regarding safeguarding againt false sexual harassment in a livein relationship

Hi, I am in a Live in Relationship with a Girl of a very young Age of 20, I am 42 years old and Married. My wife knows this relationship and although I tried to divorce, her but I could not. She put 498a case on me, I had to withdraw the divorce case, and she withdrew 498a case as well. We did a mutual agreement that I will take care of all financial needs including house, medical and schooling needs for kids and currently my wife does not know that I am in live in relationship with her in a different city. 1) My question is if I just live-in with her and do not marry her, can my wife can again put me in legal soup. If so, how can I protect myself? 2) Second, how can I protect myself from the girl legally so that tomorrow she does not put a case of rape or sexual harassment if relationship does not go well by herself or under the motivation or influence of someone else? In addition, if she begets a child how can I protect myself legally on my property or any unnecessary demand by her or the child? 3) Can a sort of declaration that we are living together and we will take care of each other but if relationship don’t go well we will separate our ways without blaming each other or putting any case against each other neither we will claim rights in any of our ancestral property or child will be entitled for my ancestral property will help to ensure that we or I don’t get into any legal soup while we are in this relationship. If relationship goes well then there is no problem but this is just to protect myself in anyway. Sanjay.