Being a single parent is a million times better than trying to co-parent with an alcoholic, says one who's been there. Not easier or more fun, just better.
Just a thought - if you do issue some form of ultimatum ("start treatment or I'm leaving"), please consider putting very explicit time frames on it , to an extent that would probably be ridiculous ("if you have not completed a recognized outpatient rehab program of at least 30 days duration with at least 80% attendance by September 30, I will consider the marriage over on October 1 and will move out by October 15"). If your ex is anything like mine, he will pore over any statement you make to find loopholes that would allow him to bargain, procrastinate, or otherwise manipulate the situation so that he can continue drinking indefinitely without any change in his living arrangements. And be sure you can follow through. He can choose whether or not to seek treatment and his choice will have implications for the actions you will take.