Drained, welcome back.
I remember when you made him leave before what he put you through. I know it well. My boss is on bar committee and I know those like your husband and what they will do to keep it hidden, well too.
I can only say Im sorry. I wish you better.
Your children are a bit older than mine, and "shocker" you'd be surprised what they actually know and wont tell you.
My only advice is keep working, keep substituting, dry close to your children, focus on you and them, meanwhile start slowly stashing a little money away. There will come a day, when appropriate and safe for you and the kids to disappear,a nd you'll need those funds.
Hang out, and remember take what you need and leave the rest, we all have our own pace and our own due time.
Should you let him know, you saw residue on table? will it really do any good? or will it start another aggressive altercation?