A lot of reviews and posts talk about how the film does a good job showing both sides of divorce equally, but I had a hard time seeing the balance.

Before the divorce, they had a good life that was obviously salvageable. She was overshadowed by him (maybe) but instead of working on that part of herself (through communication or therapy or whatever) she instead decides to divorce, take her child to LA, serve papers, get a bad-ass lawyer (when she promised she wouldn't get a lawyer), proceed to completely blind side him and his life, force him to constantly travel cross country and have two apartments, force him into a monetary loss, take away his kid, destroy his career, and have complete disregard for his welbeing.

Only at the very end when it finally goes to trial does he get a mean lawyer to salvage what he can.

I understand the balanced side in terms of both getting crazy lawyers so they can end up at a normal middle. But she was the cause of all the troubles.

When the divorce is finally over, she has regret at the end for getting a 55/45 split on custody. Her instinct was that she wanted it more fair at 50/50. But she then proceeds to give him the night with his kid even though it's technically her night, out of the "goodness" of her heart. The scene is played off as sincere and caring. If I'm understanding this correctly, instead of actually correcting the custody to 50/50, she instead uses it as a good will token to make herself look magnanimous. How is this not insulting, and indicative of her antagonistic behavior we saw through the rest of the film.

Honestly would love to hear arguments against this being a black and white case of toxic bitter emotional mother destroys happy, successful, loving father (and the family with it) because she didn't understand the concept of measured response. (measured response to his career going well and over-shadowing her)

It would have been so easy to make a version of this story in which there’s an obvious villain—put us on one side and allow us to root for an outcome. Sure, Charlie cheated and ignored Nicole’s needs, but she’s also basically trying to steal his son to the other side of the country. Some will pick a side, but I firmly believe that the movie works better if you don’t—if you can see the good and evil in both Nicole and Charlie.

https://www.rogerebert.com/reviews/marriage-story-2019

Give me a break. She doesn't sleep with him for a year and he has a one-night stand. And she's incapable of standing up for her needs in the relationship (which is highly suspect anyway given the history we witness that he basically made her career, which is fulfilling a big need) so she goes nuclear on him. But yes, don't pick a side? I just don't see it. Maybe I'm blind.