I am so sorry. I have been there, I truly understand, as do many here at SR. You will find lots of support here!
You will also hear of many people who had significant other's who drank and drank and they had no idea. Your mind does not work in the same way an addicts does, for that, be thankful. It's ok that you did not know, it would not have changed the facts anyways.
All you can do is focus on you and your children. It's really important for them to understand because that is the age that internalizes the most and easily can blame themselves. It would be good for all of you to be in counseling and or/Alanon/Celebrate Recovery, some face to face support.
I welcome you here and hope you are able to find some peace today!