Things that you can do to make it easier for the kids:
Let them know when they will be seeing their dad. Ideally, this will be regular: every other weekend and one weeknight works well for a lot of families.
Equally, it is easier for them to know when they won't see him. Then they know they can switch off from this confusing drama that's playing out around them and just get on with being kids.
Tell them that there is grown-up stuff that you and Daddy need to sort out. It helps for them to know that the grown-ups are dealing with things: it makes it feel less chaotic.
Reassure them that whatever happens, you both still love them and always will. They will worry that they won't see Daddy, that he'll leave them, so tell them when they'll next see him and put their minds at rest about the future: he will be part of it.
Don't include them in the adult stuff. Never badmouth him to them. Find a way to explain what's happening in an age-appropriate way which says, the marriage is over but he's still a good dad and I want you to have a good relationship with him.
Tell them this is not their fault. It's an odd one, but kids can feel terribly responsible for things they don't really understand. They're trying to make sense of things: maybe it's because I shouted when Daddy asked me to tidy up... They probably won't admit to thoughts like these, so keep telling them it isn't anything they've done.
Keep them updated with practicalities. They will want to know: where will we go when we see Daddy? Will he get a house? Will I stay there? Will we stay in this house or move? Will another man come and live here? It's hard when you don't know the answers yet yourself: but if you say you will tell them when you know then that helps.
I'm not sure what age your DCs are, but most of this can be adapted for different ages and stages.