You don't need any help, FTB, you're already seeing through his balderdash
It's normal to feel angry and upset, give yourself a break. I don't understand why he says he doesn't know what's going on, though. Is this supposed to be a temporary separation??
"breaking up has shown our children that we give up too easily"
Err, you've shown them that a healthy home life does not include being bossed around, insulted and frightened. You've given them an important lesson in human rights. That's not bad parenting or giving up!
He chose to say "giving up" because he wants to make you see your triumph as a failure. In fact, you have given up being abused by him.
"I have forgiven him hundreds of times. Yet when I said all this he told me I was dragging the past up."
Whether you forgave him or not is irrelevant. What happened was that you allowed him to use you, to abuse you, and allowed his cruelty, hundreds of times.
Of course he'd prefer it if you didn't remember those times, because then he could go back to using you like a bill-paying slave.
"I have told him I refuse to have weed in the house and he has said he wont give up so I am giving him no choice."
Read that again. It means you said "Home or weed - you choose." He's saying he chooses the weed. Simple.
You gave him a choice. He chose.
The reason these exchanges seem confusing to you, FTB, is because you're suffering a form of PTSD. Nothing in what he says, or does, looks confusing to me. But you have been primed, over 17+ years of this shite, to go into confused mode as soon as he starts up. Just like an ex-soldier, who freaks out whenever a door slams, you're suffering an uncontrollable reaction caused by intense & prolonged fear.
This is why we say you need to END contact with such people - you need to regain your sense of logic, and to neutralise that person's effect on you. He picked you up tonight because he wants to see whether he can still play you (yes) and, if so, to step up the pressure.
Please remember he doesn't want you back: the person you are, with all your loveable qualities. He wants his cushy life back. As long as there's a chance of getting back his obedient slave, he'll keep trying to 'work' you. It's easier than training a new one.
I'm sure you can find plenty of reading material about Complex PTSD and PDSD. Here's on page at BullyOnLine.