In the UK we have an agency called the CMA. Once up on a time it was known for being hideously in favour of the mother, basically destroying the father's financial standing. It's original aim was to get errant fathers to pay their share of maintenance costs, but it was actually used by some people as another stick to beat their former spouse with.
Following reform, they are now more in tune with financial realities and they provide a guideline, on their website, about the level of financial help that is expected from (mainly) husbands. It does, however, also say that if the former spouse isn't happy, they can go to court, but the costs have to be bourn by them and it is no guarantee that they will get more and even if they do, it doesn't alter any custody agreement, and, they also have to pay fees for the service and the amount is fixed forever more, regardless of changing circumstances.
WW/WAW's should really think about these things before they start challenging things through the courts. I don't know where you are on the planet, but I guess there might be something similar where you are.
M 45 W 52 SD22 S9 D8 BD 6 April 2015 Not living together 4 Dec 2015