I agree - no more discussions. You need to act, not discuss - every time you talk to him about this, you're just giving him more ammo.
If he leaves - great, now it's time to get some support in place for you. Don't worry about money first, worry about security. You need to contact your local DV unit (you can call 101, or google for a local number) or call Women's Aid - they will probably be busy, but they will call you back. Please do not worry that you are holding up the line for someone who is in "worse danger" - you are just as important and you deserve help too. What you're looking to get sorted ASAP is a non-molestation order - this means that legally he cannot return to the house. Once this is sorted and you have support in place then you can worry about money.
If he doesn't leave, you need a plan in place for this too. Keep your phone on you - at the slightest hint of violence or aggression (yes, aggression, you can call the police for aggression) call the police. I know this seems overkill at the moment, but it really isn't, honestly. It's not normal to live under threat of violence. You could start looking secretly at places to move to and saving up a deposit, but my feeling is that if he is already so openly violent and aggressive towards you, and the fact that you're now feeling like you cannot live with him for much longer, that it is imperative that you move ASAP. Again, there is help and support available. Council can house you in emergency housing because there is a threat (and history) of violence - you just have to ask. Women's Aid have refuges up and down the country which cater for women in your exact position (and staying in a refuge "unlocks" a number of other extremely valuable support services, which may vary by area, but can include things like counselling, specialist counselling for children, and the Freedom Programme.)
Both of these options are temporary and you would have support to enable you to find a permanent home for you and the DC. Please also look at this wonderful post from a MNer with direct experience of a refuge. And, yes, the children will probably be unsettled in the short term - but it is very, very unsettling to live in an abusive home (even if the abuse is never aimed at them) and the effects of leaving, long term, will massively outweigh this. It's like ripping a plaster off when the plaster is going septic - you can ease it away but the longer you take, the more chance that infection has of getting in.
To apply for housing benefit, you'll need 3 months' bank statements from any and all bank or savings accounts you have, 2 months' payslips if you're working, your child benefit number, any benefits and tax credit award notices and a rent agreement or letter from your landlord stating your current rent. With all of this information, new applications take 3 working days to process (I was told this today as currently having to re-apply) but in my experience, it can take weeks for the money to actually come through. If you are really stuck for the rent, you can get a crisis loan from the jobcentre so be prepared for this too - more horrible forms, but worth it if it means you can pay the bills! Housing benefit will be backdated once it's sorted, too, so if you need to borrow from savings or friends or family and you have the means to do so this is usually the best way to get around the shortfall.
Good luck.