devorce

i knew for about 3 or 4 times,that my wife had illegal relation with others,it was contineued for last 4 or 5 years and with different person.every time i maintain it for my family reputation.she dishonoured me.but at the last time when i knew my wife was an illegal relation with my son's tutor and also an other person who was from my son's school,i was helpless.by announce the neighber about this matter,i came back alone at my father house.it is expressed that i lived with my family separately adjacent my in-law house.the total matter was wel informed with my father-in law house.but they were beside their daughter every time.all document,they have captured from me forcefully.last about 1 year my wife sheltered by her parents.already i and my family went their house to rearrenge our family.but my wife dont coming also not divorce me.some days ago she tell to my brother to paid her about 5 lac rupee at a time or 3 lac at a time with 5000/month untill i death.this demand i can not fulfill because in this time i have lot of debt at market because my father died recently suffering from cancer.also i declired to give her 4000/month,she not agreed.then what can i do?plz,show me a path of getting divorce.thanks.