How to get divorce from wife after 20 years of marriage

Our marriage is in 20th year. We had a son aged 16 years.my wife moved to her parents house some 22 months back and started making excuses been I contacted her to come back.she had been very dominating nature since marriage.I tried my best to continue in marriage even agreeing to her unjust demands.Now in Jan when we once again sat down to resolve the issue.she was just B.Sc at the time of marriage.we helped her complete her M.Sc and B.ed. after Marriage.she and her brother and father put forth demands as under: 1- I should live in separate home far away from my parents home where I am staying now. My parents are aged 81 and 70 years. 2- she will not take care of my parents and my mother should cook her and my father's food herself. 3- she wants total control on her son to which my son is not agreeing. 4-She wants to work and will not do any house hold activity. 5- Her brother tried to threaten me by the mediator that they will file dowry and property case against me. 6- Asking to transfer 50%of all the property owned by my parents in her name or my father should give 50% if his pension to my wife.I didn't had any property on my name only one plot on my wife's name that to after selling another plot on my name within 1 month of sale of that plot. Can I get back that plot if I prove that it was purchased after selling plot on my name. 7- Threaten me to take custody of my son who is not willing to live with her monther. 8- insulting my parents prior to separation and after that when ever we tried for resolution through mediators. What are the conditions on which I can get divorce within minimal time. Kamaljeet singu