Don't beat yourself up. Those were obviously things that needed to be said.
Al-Anon was mainly a place for me to feel normal, still is. I have long periods of time when work interferes with me getting to meetings, and during those times, this place is a lifesaver for me. Just knowing that there are other intelligent beings who are just as knee-deep in s**t as I am, that spouses of As aren't idiots (I was really hard on myself), and that you have the right -- even the responsibility -- to create a healthy home for yourself and your children even if that means leaving your spouse... those were life-saving lessons for me.
You've told him he needs to get sober if he wants to keep you and the children.
What's your next step?
Are you ready to follow up on your threat?
If you're not, all he has learned is that you don't really mean what you say...
(It took me 2-3 years to go from declaring my AH had to choose to leaving. That time, I spent learning about the disease and building my strength.)