Well Stung, if you aren't ready to walk, what about getting tough about No Contact
and maybe getting a more formal (including visitation with children times fixed) seperation drawn up?
He keeps "getting by" with the relapses, and nothing much changes so what can you
change so there is a real, unpleasant, and meaningful consequence to his actions?
Otherwise you are going to go batshite crazy, which you don't need on top of being
effectively a single-parent and starting a business.
What do you need next, in other words?