Good for you...
...he's gone. This is simply my opinion but I believe you have shown strength and you have a chance. Stay strong. Do what you know is right, and you know what is right. In my opinion, this is a power play on his part. He knows that if you let him back in he's in charge for good because your holding him accountable doesn't stick, and he firmly believes you will let him back in or he wouldn't of started this bluff in the first place (and if you do, he'll be right).
Watch what he does when you tell him he can't come back. I predict he will be very surprised, angry, and somewhat rightous (how dare you?!?). He will show you manipulative, guilt-trip alcoholic behavior of the highest order, and will most certainly include the "you are not helping me, you don't love me, this is your fault," line of thinking in some form or another. He may also throw in a, "you are making the kids fatherless" line of bull$hit as well.
Save your children-- if they are his they are already fatherless. Save yourself-- he has already chosen his disease.
Take what you want and leave the rest.
Cyranoak