Hi Florence, welcome to the forum.
It does very much sound as though you and children will be better off away from this man.
You can find the helpline number under ‘contact us’ at the bottom of the page, they will advise you regarding finances etc
Another resource I’d try is:
National domestic violence helpline 0808 2000 247
I say this because it is abuse how this man is treating you and your eldest, the helpline isn’t just for physical violence but any form of abuse. It’s a collaboration between Refuge and Woman’s Aid, having a look at their website should prove useful.
All the best
Mark