I think all in all, you're doing a good job taking care of you and your son. The 2 of you (and new puppy) are YOUR main priority-your husband comes a distant third. (only my opinion, of course).
Just continue on the path you're taking, be confident in your decisions, and things will fall into place.
Being involved with an alcoholic just sucks, plain and simple. I'm going into my 2nd month of NC, and it's getting easier day by day-
I hope you and your son (and puppy) have a wonderful Christmas, and the new year brings us all serenity and peace...