Hi FT, separation and divorce are frustrating and tedious, even when you have a spouse who is not in denial. Convince yourself that he's going to put all sorts of propositions, barriers, irrelevancies and rationalisations into the mix, and you won't be disappointed. Be prepared to deal with some ill feeling along the way. It probably won't last, but once he starts believing you're serious, he may become angry. It's likely just a stage, not pleasant but good to get it over with.
He's not in recovery, meeting or no meeting, it's just that you saw it first hand.
Probably the kindest thing you can do is cut the cord. Be decisive, don't back down and really send him the message that this is how it's going to be. He's in denial and it's not kind to feed it with mixed messages.