I'm sorry you are going through this, Painfully. At least you got a goodbye. My A just ran away to mommy last week in Puerto Rico without a goodbye, didn't even tell us leaving. Granted, I moved out of our home 3 weeks prior due to his non-stop drinking. I moved down the street, not out of the country.
After he was well out of the state and finally did contact me, he was spewing the most hateful garbage I have ever heard in my life, all the while claiming sobriety. The way he talked to me, you'd think I held a gun to his head and forced him to live with me the last 14 years. There is no way in hell that man is sober. From the sound of things, your husband has either relapsed already or is about to.
What's been helping me get through this is focusing on things the kids and I enjoy, but couldn't do when he was around.
You will get through it. You and your children will be better of in the end. The one advantage we have over them is that we are dealing with our emotions now while they are self medicating with alcohol, another woman, etc. By the time reality hits them we will be over it and long moved on.