Some issues are just too big and complex to tackle all at once. What to do about the children is a good example.
But you can eat an elephant if you take your time and take small bites.
That’s what you do in negotiations. If you get stuck on a problem, start breaking it down into to smaller bites. Separate the issues.
Segregate the big issue of “children” into custody and child support.
Then take custody and keep breaking it down. Segregate custody into who will make the legal decisions, where will the child live, and what will the time sharing schedule look like.
You can even break down legal decisions into separate pieces like who will decide which doctors to use, who will decide where the child goes to school and who will decide what religion to raise the child in.
Sometimes it’s easier to reach agreement with a series of small decisions than trying to tackle the whole thing at once.