What can I do to ask for retroactive maintainable

I was married in 2003 and legally we have not filed for a divorce yet but have been living in two different countries the past 3.5-4 years. My son had to move to Germany with his dad 3 years ago since he opted out of paying his school fees in Delhi. He paid for the last few months of our shared apartment until the lease expired.after that he reduced the a lint he would send me for the living expenses from 130000 a month ( he paid this only until the lease expired since it was in his name ans he was obligated to it. He then paid me 70000 for a few months which was when my son was still living alone with me in India. After my son moved permanently to Germany, my husband paid 30000 a month for a few month again as salaries for my maid and driver who I was unable to afford and had to fire all staff, I had earned some money as a freelancer during the last years together in India but with no home or support system I moved into my brothers house And stayed with for almost 2 years. I haven’t received any payments from my husband in the last two years or so. I want to know what is my best course of action to maybe get a small amount of 20000 a month retroactively for the past two years or so. We had agreed to two tickets Frankfurt to Delhi every year which he would pay, since the lockdowns etc there has been no ticket purchase so far and my son turns 18 in November so would he not be regarded as a child who needs to travel/ see his mom at least twice a year even though he’s an adult legally? Also my husband is a lawyer and for many years throughout our marriage certain amounts would be saved into a pension fund in his name, he also has a hefty life insurance and since my mother in law passed away a few months ago, he’ll get a share of her personal items like her furniture and what’s in her bank account Her jewellery etc etc do I have any right to ask to see the accounts there and claim anything from that side? I have two sisters in law and they have shared the jewellery between themselves already, also through our marriage hes been the primary earner, I was looking after the whole house and my son singlehandedly Witt no help for almost 6-7 years from any staff or babysitter unless it was a one off. The wedding in India was paid for by my parents. I also transferred him 14 lakhs in 2013-2014 to invest via his bank, he lost some amount but then the rest of the money was taken out to pay for my sons school and rental etc. what should I be asking for and what should I let go. I would not like to file any criminal case against him if he cannot appear on the court appointed date since Germany and Delhi are not next door to each other and it would take a lot of planning. Can he refuse to appear for the Indian court summons in which case what are my options. I currently leave r earned in two years since I Freelance as a wedding planner and covid halted all my operations.