There is a very great chance he physically stops you from leaving & gets violent as you are rebelling.
Don't tell him you are leaving.
Go the CAB & sort out your position before, you have lived like this for years, a few more days is doable.
when he is out, you pack the stuff you need & take it to work/friend/parents. be careful he doesn't notice things missing.
at this point you should organise any money that is yours, half the savings, all you salary etc into a new bank account with on line log in.
Could you get a cheap spare phone ? (hide it obviously at work) I worry he has spyware on your existing phone.
Get copies of any paperwork, savings, pension scheme, house deeds, payslips, all & everything you can find. If he has hidden birth certificates & you know they are locked up in a drawer you can break it open as you leave, or order another on line.
You can call domestic violence number & forward of imminent danger, if you feel he has smelt a change coming, & think he could be violent.
personally I would not say, I've had enough I'm off, I would leave & send an email.
He WILL promises to change, go to therapy, cry, sob, offer holidays, flowers, he will say it stress at work, his nasty childhood, he will also say you push him too far,
Do not believe any of this bullshit, it is the cycle of abuse, to reel you back in.. if he sees it doesn't work he will then threaten to take the kids away, to ruin you, to throw you out, you will have nothing. Its the script.
Don't listen, the great thing is once you have left is, you can refuse to answer the phone, not reply to email, or simply hang up.
It is a massive challenge, but you can do it,
EVERYTHING will improve form the minute you get out.