Wife is torturing me and blackmailing me, want to file divorce

I got married in 2013 feb. Since day one my wife is always harassing me with her words or blackmails me saying she will kill herself. She abused my mother and sister too for no reason. Every day in one or the other way for silly reasons she gets angry and goes out of the house on to the road shouting like anything. I never know what is her problem, she quarrels for small reason and goes to her mom's place. She got pregnant and didn't come to my house till 1 and 1/2 year. During the times of pregnancy she used to blackmail me about aborting everyday. After delivery also She came back to my house leaving my son at her mom's place. She never allowed me to come close to her after delivery and also before pregnancy hardly 3-4 times. Post delivery also she didn't change anything everyday she quarrels with me and abuses me like anything. Recently i got know she is having some extra martial affair but i don't a concrete proof. I am vexed of her behavior now. My mom's health and my health is not well these days. These days she is harassing me saying she will kill us as we are not listening to her. She is threatening to file case with police that we asked for dowry and tortured her. I have thousands of SMS from her abusing me and my family, I want to file a case on her torturing instead and also Planning to file divorce kindly advise.