OP, please repeat to yourself again and again "this is not normal, this is not OK, I am not crazy, and me and my children do deserve better".
I think many women rely on others to validate their feelings (not wiser-than-thou BS, I do it too) and when the person in front of you is outright ignoring you, minimising your concerns and invalidating your thoughts, it is hard to keep a grip on what you know to be true.
Write it down. This thread is a very clear indication of the way that you feel and it's a catalogue of aggressions and abuse. Start writing everything down - remembered or ongoing - that upsets you, frustrates you, times you have been exhausted or intimidated or felt like you are screaming underwater. Keep a paper diary (keep it hidden) or send emails to yourself at your new, secret [email protected] address, and read it whenever you're doubting yourself.
In order not to drown in it, you can also use this diary/email log to write to your future self about how you want to feel and the things you want to do when you're free of him. Write to future Mousey about how calm and relaxed your family home will be. How your boys will spend a lovely afternoon playing with your mum who just popped over to give you a chance to study. How after bedtime you'll both have a glass of wine and a chat, before heading off to bed by 11 pm for a good night's sleep. I bet that is currently an unimaginable scenario right now.
Validating how you feel, listening to your own instincts, and visualising what you actually want will all help you to act and to get away from this toad.
Someone up-thread said "baby steps", and they are right. Leaving feels hard and scary, and there are so many things to sort out... but individual tasks are achievable. Break it into steps.
Call Women's Aid
Set up a new, private email address
Set up a new bank account (all docs to your mum's address)
Stop all "wedding saving" and divert this to your "secret" bank account
Speak to your GP who might be able to put you in touch with local services
Go on Entitled To website and get concrete figures for income support
Speak to the CAB if you can get to one
Write everything down in a diary or email log
Get copies of boys' birth certificates and keep passports safe
ONLY IF YOU FEEL SAFE TO DO SO
Change the login on your Natwest account and report your card stolen
Stop performing wife duties for your partner (you have asked for more help, stop washing his uniform/making him lunches/cleaning the bathroom/hoovering/etc.)
Your eyes are open, everyone here is rooting for you, and deep down, you know you're right.