You're doing so well GoldenDog! Great approach and recap. I second Dandylion's suggestions that it wouldn't hurt to let the kids know that a big part of the reason is the alcoholism. Because kids usually think the behaviors they observe growing up are normal, they will have a blindspot to it, but it will still affect them. Hence, your daughter suggesting therapy at this point.. because what's the problem? It must be mom.. It does seem as if your son has some perspective on it though.
I'm not suggesting their were beatings and extreme events, although some of it did sound pretty bad (the parties, nights out, etc), but it is the subtle things that happen in families where addiction is present. The lack of honest communication and personality changes (when drinking), the often chaotic environment, lack of or strained physical and emotional intimacy between the couple, the attempts to make everything appear "normal" to others outside the family unit, and the compensatory coping behaviors used by the non drinking spouse (you), who has to hold down the fort, do the planning and organizing, etc.
I had no idea how badly my family upbringing of chaos,, personal loss. alcoholic/absent dad and overly strict and religious mom affected me until 10 years ago, when I was first told about ACOA. It was an epiphany. Suddenly, so many of my unhealthy relationships and other personality issues such as codependency and drinking to control my emotions had an explanation. I have many of the ACOA common traits. So yes, I think some gentle and well-considered explanations, and perhaps an introduction to their literature or a meeting at some point (if necessary) would be in order. Might keep them from making bad decisions and choices later in life.