Wife tantrum

my wife is not going well with me and my mother, whenever their is a fight between me and her she trying to involve my mother in it (senior citizen) and disrespectful towards her. I am not happy living with her and in the bad marriage beacuse of my girl child se is 6 years old. My wife is so emotionally freak that if I said something to her she started weaping a lot. She become active in the night like a crocodile in the water and say foul language to me, disrespectul towards me and my family. I called her family many time and make them aware about her behaviour but no benefits beacuse they favour their own daughter and I said many time that their daughter is having suicidal attittude soemtime she trying to drink the phenyl, sometime cut their wrist and sometimes ran away from the house. I am always givinh her more time to improve but she become to his natural behaviour after somethime. In the night if their is any argument then she will not allow mw to sleep, she wake me in a continous interval of time and say to me to compromise. I am fed up with this behaviour, what to do please guide? My salary is good and I am IT professional by profession. and my wife is BA graduate and 2 years diploma in elementary education. How much maintenance I have to give her in case of seperation? Any help would be appreceiated.