Alcoholic husband

Hi i am married for a year and half. Mine was a love marriage where the love is gone. After my marriage i found out my husband is an alcohol addictive. First three months were hell den came the apology mode nd i dont wnat to loose you. My in laws are very supportive, but cannot do much as the son doesnt even care for what they say. Now i am 8 months pregnnt. Throughout my pregnancy i tried to give him reasons to cut down or avoid on some days. But i have failed. He will everyday look for a reason. I dont want to give a future of a drunk father to my child. He says d ababy is very imp to him but i don't believe as none of his actions show. He has a lways been irresponsible which bothers me Aswell. Since marriage we dont have a healthy s*x life and this pregnancy is just unplanned. I tried talkng to him but he screams and fights even on this. First he said coz of stress he couldnt focus and now as i am pregnant. I feel torturous and unhappy in this marriage. I wan to file a divorce, please suggest how tp go bout it. When i tell him bout separation he says do whatever or runs from the situation. I wnT to end it once and for all as i dont see him quitting on alcohol. Please suggest.