Feel for your OP, a real mixture of issues.
I think one of the things that jumps out at me is the changing landscape of your profession - your job is going, does that mean in 2 years there will be lots of similar colleagues all job hunting at the same time?
Purely on paper your new job sounds like it ticks a number of boxes: securer (well as secure as any job), much better money, continuing your career and offering you a role now before there are more looking for a job.
You also mention shorter days, how short? Would you be gaining some DC time on those days?
The issue of who is the breadwinner - can anything be done about that? Or do you "just" have to accept it? It must be hard being the breadwinner if you don't want to be, but with your DH's lack of earning potential (from what I take from your post & at this point) it sounds like you might just have to try to embrace it.
If he continues his "out of hours" job then your children are still being looked after by a parent, just not you. If that is important to you as parents then you should try to congratulate yourselves on creating a set up where you do this, many would like to be able to but cannot etc (don't mean "don't moan" but just pointing out what you do have).
Although I do echo baby s point, perhaps it would be better to increase your family time with him reducing his hours, even if it is just to enable you both to catch up on sleep at the weekends.
I have to say personally my DS thrived at nursery, so it could be worth considering trying it if your DH wanted to try to work in the week/retrain etc.
It is also worth thinking about the next 5 - 10 years? Some would argue that it is better to be around for teens more than little kids esp as there are limited childcare options for teens.
Could you see this new role as a way to save up/move area with the longer term plan of reducing hours/going private (assuming there is a private market for your type of counselling)? Maybe DH could retain during this period so he could hopefully kick start a career when you are then reducing your hours etc?
Finally, have you tried everything with regards to the sleep? You sound like you are resigned to it. It is very easy for me, a stranger on the internet to say this, but if you haven't I would chuck everything at trying to get them to sleep. IME everything seems overwhelming and infeasible when tired and years of it is just so draining.
Good luck.