Here's your problem: you keep referring to "OUR" and "WE" and all those nice married words. Except that, in legalese, there IS no "our" or "we" in child custody and support. The "we" was your wife and her X. The "our" should refer to the kid/s from the relationship between your wife and her X.
You can't stand up for her in court or mediation. You can't file any papers. You can't interfere. Legally. (This IS a legal info site, you know. Not much else matters.)
The amount of support paid? Not your business.
The amount of time spent at mom's vs. the amount at dad's? Not your business.
The relationship, legal or otherwise, between your wife and her X and their children? Not your business.
Do you see the problem now? IF there's a problem, it's your wife or her X that needs to take care of it. Not you.
Edited: I forgot to add that your snotty little 'tude ain't helping either, dude.