No more drinking

My life is actually really great so I dont know why I continue to drink.....everyday I say this is the last day i drink. How i manage to make it through my daily life without incident i have no idea. Addiction runs in my family. My aunt died at 49 from liver failure from drinking. My mom pops pills. My bio dad is/ was (I have no idea if he is still alive I never met him) an alcoholic. I have a wonderful fiance, two beautiful daughters, a wonderful career, a beautiful home.....life is good. Why cant i stop? Some times i drink as early as 5 in the morning. I never drink enough to stumble around drunk, its like I am drinking to get through the day with no shakes. If i dont drink I cant sleep. Yesterday I drank an entire bottle of vodka through out the day a shot here a shot there, and still managed through the day, made dinner and what not. My fiance had no idea. How is that possible? This i feel is my breaking point. To be able to drink that much and still function???? Thats too much. I decided to join this group and hopefully find the support here and be able to come here to vent and talk instead whenever i feel the urge to go get a drink. Thanks for listening.