explodingkitten what your suggestioning is now illegal because of the childcare laws (ridiculous in my view).
Congratulations OP, according to this thread you are the next Virgin Mary, having impregnated yourself.
Look at what work is available locally, work out what that means your DH has to do to make it happen and have that on hold.
Personally, I think he's moving the goalposts.
If you had have waited for the NHS and needed childcare because of being ill, it would have cost more.
You have a solution, you can cut back and it should be the whole family. Because I bet you're the anchor, so nothing to do with your health is for just you.
Youve had some twatty answers and it just shows what little value is placed on SAHMs, especially with four children.
As said, you'd still be on Mat Leave.
Does the baby take a bottle, at present?
If you do one 12 hour night shift in a Care Home, your DH will have fun and games sorting that out.
Before any answers were given to your thread it should have been asked if he is a hands on Dad and is willing to do more.
Job search, meanwhile to get him ised to having the children on his own, I'd recommend meditation and breathing exercises. They are fantastic for anxiety.
See how happy he is with that, before you make him being sole carer permanent.