((Rancher))
how heartbreaking for you & the girls - at their ages - I would be very surprised if they don't already know more than what you think, but it's their MOM - they are affected by the family disease of alcoholism - they are playing a role in this too - they are going along with the "game" to try to keep peace & harmony in the home too. At no matter the cost. My girls did the same in dealing with their step-dad for many many years.
If or when you do leave - i agree with healthy compassionate honesty - lots of reassurance that THEY are still loved by you and that you would like to still be a part of their lives (if that is how you feel)
You can still reach out to them thru cell phone, cards, school activities, etc. - that will be very important to them - (my step-daughters & I still are on good terms & stay in contact a bunch)
Just from my experience, it is important to let them know that it has nothing to do with them - that they are still precious to you and you will always care for them. They will probably need that reassurance.
I know I said that already but truly all children need that - as an adult child of an alcoholic father and a co-dependent mother - I knew they loved me - but that low self-esteem & self-acceptance was never there for me - they did the best they could but I could have used a little more positive reinforcement as a child.
Best wishes for you as you take this journey - for you, your wife & these precious daughters!
PINK HUGS,
Rita