OP, I know this situation is (fortunately) hypothetical for you, which might explain your delusion.
Firstly, in the vast majority of cases, adults don’t behave well, or in the best interests of their children, when it comes to divorce. This is a generalisation but I’ve found it to be true: the NRP is usually the man, and usually is unwilling to do more than what they absolutely must. And even not necessarily that.
The idea that a NRP is paying towards a mortgage on a property they aren’t living in, as a matter of course, is laughable.
I’m in Ireland, our system is different. No CMS which is both good, and bad. Bad, because there is no systematic way to enforce maintenance but good as the CMS rates seem appalling low in the UK, so generally, once formalised, maintenance is much better here. The problem is in the absence of parents being willing to agree, you must go to court, still usually needing a barrister, solicitor at the very least. It also takes ages, during which you are likely to be getting nothing.
That was my case, a 10 year battle to get divorced, and get maintenance. Before that I got varying and sporadic amounts, had to pay the mortgage on my own BUT in court, had to agree to pay him a very significant sum (just short of 6 figures) to buy out his interest. The house is legally mine, however, in the bank’s eyes, my ex remains on the deeds until they are willing to give me a mortgage in my own right (which they won’t yet)
I could go on & on. My ex doesn’t have the DC to stay, and sees them when it suits. He has a great life, and still resents having to pay maintenance - he sees it as supporting my lifestyle, being unaware how much it actually costs to raise 3 DC.
Also, this idea that you choose to be nice to your spouse to avoid divorce & what it entails, well, great. But don’t make it sound like divorcing was just a whim or easy decision for those of us who had to do it. Some of us went through hell, and had no choice either.