Actually op I’m hugely sympathetic. It feels impossible to leave when you have SO much going on in your life. Teaching and all its overtime; young kids who need so much care and attention. It can be done.
You need to start planning. You aren’t in a hurry to leave, so be clever about this.
you have credit card or other debt - well that’s financial abuse if you’ve been out of work to be a sahm and he’s forced you into debt. Does he know? Could you talk to him about him clearing your debt?
if you are doing all the life admin then tell him straight “I need to clear my debt now I’m working. Therefore from now I will be making changes so I can get my finances under control again.”
Start cutting your own hair and the kids hair yourself with scissors or just let everyone’s hair grow long. Make sure the in-laws see the kids a lot and when they comment say very brightly “well I’m in debt because obviously I had no money when I was a sahm and dh keeps all his own money, so I’m just economising really as debt is so expensive, and now the interest rates are rising I’d like to clear my debt and become a saver again!”
Second-hand everything for clothes including coats and everything else you can think of. Shoes for older kids should be new maybe except wellies and slippers. So much cheaper. I’m not financially abused and I buy second hand - fabulous stuff on Vinted. My mil stopped commenting years ago as she knows I won’t change.
For meals - if he leaves you doing the cooking, then buy Basic everything. Quick and simple Vegetarian food on a basic meal plan for him from now on - pasta with basic tomato sauce, cauliflower or macaroni cheese, barley and lentil based soups in the slow cooker, toast with baked beans. You can add protein for yourself and the kids (a fried egg, a slice of ham or chicken).
when it comes to these luxury holidays who is running around booking, making sure the house is clean, organising foreign currency, packing? Just stop. You are now busy at work.
When it comes to birthdays, Christmas or religious festivals, who is running around organising, making food, buying gifts, welcoming guests? Just cut it all right back. If he invites guests over then they can have a cup of tea, a nice chat and a biscuit or some basic peanuts. Again if it’s the in-laws visiting just make them aware you’re broke. They are probably unaware the misery he’s making you live in.
Find an available, regular babysitter and start using them. This will be worth it’s weight in gold when you leave as the kids will be used to spending time with someone else. Use the time to go out. You could house hunt, or take up a hobby or just take your marking to a local pub or cafe and sit and do that! Find yourself again.
What I’m saying is - start “practising” your new cheap lifestyleand build your escape fund. Try and start drawing small random amounts cash every week at the supermarket or petrol station or anywhere with cash back eg £80 or £50 or whatever., keeping it safe and then and paying it into a separate bank account (set up a brand new account at a different bank to your normal one, choose one with a local branch). It’s untraceable in a divorce.
Does your dh give you no money, ever? Does he not let you see bank account statements?