Divorce for the sake of the future of the child

Me and my wife are fed up of the relationship & I really want to quit it out. I have a 2 year old son from this relationship. There has been a lot of mental pressure and the 4 year marriage did not turn out as expected. Having a child did not reduce the friction for long and the thing have been really bad. The fights are becoming physical and words have turned vulgar from both parties. The relationship can now to termed abusive and we go out of the way to speak to each other which we usually wont in good mind. The child is suffering due to the constant and frequent fights between us an I really do not want him to grow watching this stuff. Why after 4 years? The constant push of thinking that tomorrow the things will get better has failed. Loosing the custody of the kid or departing from him actually crushes me to ground, that is why the delay. Also I have been thinking how would he grow up in a community where divorced parents are not very common and that would affect him mentally.