The underlying feeling I'm getting from your recap is subtle, but it's there -- there is a codependency around being there for family no matter what. It is so commendable that you are striving to say nothing negative about AH. I'm happy that your son seems supportive. I would echo what others have said, that now is a good time to start AlAnon / ACOA resources to help work through issues with and education around alcoholism and the effects on children that have grown up in families with alcoholism present.
There is nothing wrong about disclosing that the alcholism has caused unsolvable problems, ones that won't be solved by therapy. Your daughter seems to be expecting you to step into codie mode to hold the family together and bite the bullet on your own feelings and needs. This is such devastating programming, because eventually your children will need healthy relationship skills, and this is a slippery slope for adult children of alcoholics.