Welcome ebroadcast,
I too have only just join and are situations are similar in ways.
I have an AW and a son too, who is 7.5years. Even though she has never driven with my son "drunk" to my knowledge, she has driven with him whilst she was well over the limit and her senses impaired the morning after. She would drink most evenings and think nothing of taking him on the school run in the morning. Which not quite as bad still makes me angry.
I believe my wife also began as a social drinker and the alcohol has just crept into the house more and more. The past 3 years it has increased massively.
It is a positive that your son is at an age where he can understand with maturity what is happening and you definitely in my opinion done the right thing by telling him.
I still love my wife but don't like the ways she has acted, these are tough times but the more i read about the subject, you have got to do what is right for you as you have been doing what is right for everyone else for far too long
If you would like to private message me at any time to get another dads perspective, please feel free to do so.