How to manage the threat of my wife & mother in law

Due to incompatibility my 1st marriage was broken and obtained divorce in 2012. As per my prayer family court given me custody of my two children whose age were son 13 & daughter 8. I brought up them with my old parent. My son a scholar now admitted to phd at IIsc.daughter just admitted to BA eng hons. Iam a self employed professional now age of 50.I was not in mood to remarry and focused on d upbringing of my children. The marriage proposal of an issueless divorcee of 39 age who has obtained divorce in december, 2018 came to me in 2019 jan. The woman had bedridden father who died july 2019, two unemployed younger brother who are lazy & useless, having no house etc showed pity on my condition of my old parent, my old age etc and d same time draw my sympathy on her situation. Though we both have a bad experience in connection of our early marriage think it proper to accommodate for rest of life being " Sahara" to each other. My parent and children admitted her without any hesitation keeping in view of our loneliness. I expressed my inability to have a baby as I hv health liabilities of my old parent 77 & 72 and marriage of daughter in near future and expressed as I signe handed manage everything , I hv no energy to struggle rest of life with another baby which they admitted in disguise. The marriage took place in march 2019. Soon after d marriage they came to their true colour of poor socialisation. Every day threatening me to face dire consequence, to destroy my children future by false implication, book me jail, if a child is not provided along with Other finalcial demand. Now she left d house by threaten to face various cases. I am residing at d house which is my mother name. I hv only one plot of 2000 sqfeet & savings of only 6 lakh Fd and loan of 4 lakh against that Fd. This is my total assest and IT of net income 3 lakh. Please be kind enough to suggest how to overcome this panic situation.what remedy availble to me. Now it is my observation that i hv been trapped.How protect my children future to whom I hv given my all my effort, labour & pain. I admit that I committed great mistake. If I retain my thought of 2012 to 2019 then I would not attarct such measurable situation.