How to make DP see that we need to split?

[Mcmuppet]

We have 2 young DCs. DP and I are not getting along at all and I have been working on us now for 4 years. It feels its gettimg worse. Yesterday, we argued infront of the children, DP threw a basket across the room.
Things have gone too far now, we need to split I think. He is a lovely, laid back person usually and I think we are so incompatible that we are making each other ill and turning each other into horrible people, which we're not.
The youngest DC is a baby and O jave nowhere to go, no family to stay with. He has plenty of family that he could stay with. I need to put it to him tonight that things have gone too far, that we need to separate. I need to ask him to consider moving out for a while.
He is likely not going to accept anything I say or acknowledge that we need to go our seperate ways. He will argue with me about why what I am saying is unreasonable and he will probably sulk and ignore me.
How do I get him to take me seriously? I cant leave, I have nowhere to go and unless he leaves, we're trapped into staying together.
What can I do?

The words 'I have been working on us' concern me. A wise lady once told me 'one hand can't clap'.

Arguing in front of the DCs is one thing but throwing stuff takes you into domestic violence territory, and should the police be called to an incident where the DCs are present, Social Services will automatically be informed.

Is he that selfish that he'd risk upsetting and limiting access to his own children?

You sound afraid of him, not a good sign. Don't have that conversation at home unless you have someone to call upon should it get ugly.

Do you rent or own? Whose name is on the rental agreement/deeds?

You'll need to ignore any sulking and stop acting like his partner i.e. no washing, cooking, cleaning etc for him - he'll never accept your decision to separate if you send mixed signals by still acting as one half of a couple.

Whose house is it? Because if he is on the tenancy agreement he may not want to move same goes for owning the house. Is there a possibility that you move out instead? Seen as he is being firm with not moving?

I’d tell you that you were unreasonable if you told me to leave my home and children too.
I think you need to work out your long term plan first.
Sounds like there’s no divorce as you say “DP”. So you need to look at your housing options, your work, any joint assets etc - and present him with the end game, not just a suggestion that he go sofa surf away from his children.