This.
The very first thing you need to do is get you head in the right place: you are as of now "separated but living in the same house pending divorce".
You are now a "single" person, co-parenting your children.
Recognise this and come to terms with it.
So following on from that, you and DH are like flat-mates. If you would not do something for a flatmate, you don't do it for DH. So no laundry for him, etc.
Start a thread in the Relationships or Divorce section as @BilbaoBaggage said.
Decide who gets to keep the main bedroom and who moves to the sofa or one of the kids bedrooms.
From now on, you can't trust him to be fair and reasonable (he might be, but don't count on it). So start gathering financial evidence, just in case he turns nasty and decides to try and hide assets or cheat you out of a fair financial settlement.
Then discuss what to do about immediate finances pending the divorce. Do you want to cook and shop totally separately? Each have your own cupboards in the kitchen? Or maintain basic "household supplies" like soap and ketchup for now? It may make sense to keep a joint bank account open and leave in place the direct debits for household bills, but start the process of splitting finances as far as you can - e.g. put half of all savings into your own name, and both minimise the amount going into the joint just to cover monthly household costs and no more.
Do you have income? Do you need him to put more into the joint account than you? Will he do this?
Alternatively, each do your own shopping, close all joint accounts immediately, cancel monthly direct debits, and agree to pay half of each bill when it arrives (this will often cost more as you lose the DD discount), then he has to pay you maintenance for the children pending a final split and financial settlement (assuming you will be doing the shopping and cooking for the children).
This option is more complicated and can trigger conflict, so you may want to avoid it until one or both of you actually move out.
(You don't keep any joint accounts after you start living in different homes, which comes later).
Then see a solicitor, and assume he will be doing the same.