Want divorce from my wife

Respected Sir, Myself Renik Mandal (muslim) married for 3.5 years and have a baby boy of 2.5 years.Since the initial period of marriage nothing happening good with my wife.meanwhile she committed a suicide and narrowly saved by us.this was before her pregnancy.later things seemed stabilized,but I was gradually being disturbed with this relationship and ultimately adhered to an extra marital affair.I told her about the incident and tried to convince her about the unworthiness of the relationship.I offered her to get divorced with or without the child in any condition, I repeat any condition.She agreed to talk to her family.But eventually it was unveiled that she was not interested in divorce in any condition and told my parents about all matter.They took her side.I told her that ok I will not divorce you and I also end my extra marital relationship but I can not accept her mentally and will not be able to love or trust her anymore.That night I slept in different room and at around midnight she came in the room with a knife and had an attempt to kill me as she thought I was talking to someone else but it was not true.I told my parents about the whole matter and they sent her to her own home.After six months my parents bought her back without informing me. I left my home and I am out of home but in the same city since previous 2 years.during this period I have not communicate with her in any manner.She,my parents and their family did not want divorce.But now I want to divorce her legally at any cost.what should I do.