Unemployed husband and childrens abandoned by employed wife

I have lost my job 7 months back due to Covid Pandemic. At present Im unemployed and without any stable income to run my family expense. My wife is employed and has a steady income. We are married for 18 years with 2 childrens. Till 2016 I beared the entire family expenses, from 2016 my wife started bearing the school fees of 1 child thats it. Since my company was declared sick and my salary was 40% slashed in end 2019 in a mutual meeting after lots of grudges my wife agreed to pay Rs18000 per month and I contributed Rs 20000 as monthly family expense and both our amounts were deposited in a Joint account. Last 7 months Im unable to give Rs. 20000 as I am unemployed but she is also adament of not increasing her contribution. In this situation also I have paid 8 months school fees Rs 24000 for our 1st child, but my wife has stopped paying school fees for our 2nd child for the last 9 months, even though she was paying this amount since 2016. I had also requested her to pay the electricity charges as Im unable to bear such huge expenses ( Rs. 4500) at present, but she refuse to pay. She is not at all interested to live with me and care our childrens. She is a working women and have several boyfriends. Rs. 20000 what she gives is spent for maid, tutors, milk around Rs 16000. With no choice we depend on Rs 4000 plus my bit of contribution for the entire months ration. Can Rs. 4000 feed 2 adults and 2 childrens? This is going on for the last 8 months, my children stay with me as Im there caregiver, I am trying for new job but still not successful. Question 1) How to address the financial issues legally. 2) Can I file a petition for seperation? Though we are separated under 1 roof for the last 1 year and have no conjugal relationship. 3) If seperated can I claim financial aid till I get a stable income as legally she would still be my wife and has responsibility of my well being. 4.Can I claim Child Custody ? as she is working and if childrens are with her they would be kept with aaya, or maids. As my children are now with me and Im there sole caregiver.