Hi there and WELCOME to SR
This is a wonderful place to find support, and sometimes a bit of off-kilter humour.
I second (or third) the Al-Anon recommendation. That and SR saved my butt when I was dealing with my XAH (ex alcoholic husband).
The fact that there are young children involves in the situation makes things a bit more...tricky, because your trust in your AH (alcoholic husband) puts your kids on the line. It seems you may have to take long term steps to ensure that he is never left alone with the children, because he does not appear to be in control of anything at the moment. Whether he is drinking or drugging, he is not a trustworthy caregiver right now.
I know it sucks to suddenly doubt your long-time partner, but you have no other choice but to do so for the sake of your children.
Please keep posting here as much as you like. SR is always open!