Somehow I doubt two humans amicably separating will have as much trauma. Some for sure but it's not like they'd be hurting for paying for some therapy.
I'm very, very far from judging these parents, everyone has the right to be happy. But using the well-being of children as an argument is often just a way of rationalizing one's emotional choice. And I'd venture to say a more honest approach could be more beneficial for everyone involved.
So women will say (and subconsciously think and believe) that breaking up the family is good for the children, when nobody else would agree, so that her decision looks good.
Hence the 50% divorce rate with 70% of those initiated by women - they set aside the effects on children.
“I Put The Kids First.”
https://www.youtube.com/watch?v=gSez-PNiMJM
You can read a similar example in this quote by Hillary Clinton:
https://therationalmale.com/2015/09/02/solipsism-i/
Obviously the primary victims of war are the combatants, mostly men, but that doesn't fit her narrative, so she makes up nonsense and no doubt believes it, even though she has legal training.
And obviously, there are many cases where this argumentation is valid and every sane person would do the same, e.g. when the partner is getting violent, abuses alcohol, drugs, and so on. I feel even verbal aggression is enough: if your partner is calling you names in front of the kids, what kind of role models are you for them? In this case, if this is a regular thing rather than a single case, I feel it's better to part ways - and it will be better for kids.
A close friend’s parents are still together, but he was raised hearing from his mom that she was staying in the marriage because of him. It was a regular occurrence. Only when he hit college and started talking about it more did he find out his mom said the same to each of his older sisters. The sisters were possibly able to brush it off more because they were closer. Also, the dad was the target of a lot of anger in the house, and my friend would draw comparisons from his sisters and mom, i.e. “you’re just like dad” was always a criticism to him.
So elsewhere in this thread, someone used the caveat “as long as it’s not toxic”, and I think that’s actually a nice generalization. My friend’s childhood experience was pretty toxic.
I wish there would be an easy retort such as "if it's toxic then get out", but generalizations never work.
When I was in a toxic relationship for 6 years already and had 2 kids under the age of 4 I wanted to get out badly and what prevented me what the judgement from others but also of my future self. So I stayed for another decade before it all imploded on its own. If I'd thrown in the the towel when my gut told me to I'd have never forgiven myself.
It's an impossible problem IMO in which there is no "correct" answer other than just "make a decision with the best intention and which are able to live with".
Sorry to hear of your situation. Agree, by no means are these issues clear cut in any way.