Just want to say that you have found a wonderful supportive community here.
It does seem to me that your therapist has advised you well, in my experience, some don't understand addiction as well as we might expect...you are trying to take care of yourself and your children, and you got away...even for a short time. Very true what has been said here, alcoholism is a progressive disease, so things will not get better unless your AH gets into a strong program of recovery, and it takes time. He has already driven drunk with your child in the car...thank goodness no one was hurt. There is no reason for you to think it wouldn't happen again.
Stay and read all that has been recommended, and you will find strength and clarity.
What you said about "gaslighting" was so familiar to me. I found this site when I googled "alcoholic insanity". I found this site, and it saved me.
Keep reading and sharing. You know what you know, don't doubt yourself.