Good for you for deciding to go to Al-Anon! Now don't forget to go! Reading posts here on SR will help you learn more about alcoholism and alcoholics too. But, there's nothing like Al-Anon for learning about this whole mess.
Good for you also for not doing anything else he can do for himself! Take the things he says to you, especially about the mother of his children, with a grain of salt. Remember, there are two sides to every story
Take good care of yourself and keep reading