Hi Stu
I'm going to try to suggest some things. I think the first thing you should do is talk in private with your girlfriend that you two have to come up with a plan, and neither one of you backs out, especially in front of the kids.
ONE NIGHT AFTER SUPPER call a family ,meeting. Have something ready as a reward for the kids sitting through the meeting and paying attention. The meeting needs to be as humanly short as possible and in language the kids understand-BEFORE HAND-set up a chart-something like this-seven days a week, and hours.ALL nAMES ON IT-all-and in the space where you as DAD is write work for "our the family". Right underneath that put the son who is having difficulties.Write his name-then "sleeping" if it's his bedtime-That's his "job" at night-I wish I could mail this to you-under that list his routine and chores, and rewards. Rewards can be what he wants most, time with you and, or mom. Do that for the whole family-When I wrote on a paper my responsibilities, Nancy, Chauffer, nurse when kids are sick, menu planner, wash laundry, run errands, grocery shop, clean, counselor=my list was long-the kids went like this, CHarles-school, homework, room clean, chore, play=I didn't have play time=important for all-there's so much more to this-I would love to write you again-Rewards can also be help with supper, , make amenu for the week, shop accordingly, helps with spending-rent a movie,Paint with him-I mean but acryllic paints, canvas boards and some cheap paint brushes. Doesn't matter if u can or can't paint-it helps and is relaxing-start with you doing it close to him-he'll ask what you're doing-tell him you're trying to paint-start with skies and an ocean, anyone can do it-who knows whre that may lead. He may ask, can I try it too-you then tell him, if he has good behavior with mom while you're working, then you'll paint with him on a day when u pick. Ask relatives to buy him gifts that are educational, such as a photo book which is plain and simple so he can copy from to try to paint-paints-legos- small cars with books to learn about them, but mainly to think about what they buy. You can even have small party if you have friends and family, for all the kids-explain what you're doing-trying to make it more family progressive-the invitation could be, "just for nothing, because we care family" explain to your kids if the friends and family can come over, it's because we care about US as a family-I'm not trying tomake this sound so complicated, just ideas. Good Luck into your recovery and life.
Nancy