Or they learned to dislike each other. Being kind to a constant source of stress in your life isn't easy.
But the can't always control it, the blame game in life is much more emotional than it is logical, and emotions are tough things to control at the best of times. And it's pretty obvious that someone in a failed marriage probably lacks the ability to control their emotions. The reality is that people say "OK I married the wrong person and now I'm stuck here for the children and I hate my life and all the people that are part of making suck". It's easy to take the high road when not in the situation but down in the trenches of reality life isn't that cut and dry.
I didn't say it was easy. But you are either committed or you aren't.
emotions are tough things to control at the best of times.
True. But if one is a parent, they'd better LEARN to control their emotions. And if they can do it with the kids, then they should be able to do it with their spouse for the sake of the kids. I'm a firm believer that, if you treat someone with kindness, unless they are mentally unbalanced, they will begin to respond to you in a different (better) way.
The reality is that people say "OK I married the wrong person and now I'm stuck here for the children and I hate my life and all the people that are part of making suck".
If they can't be kind to one another, then staying in the marriage 'for the sake of the kids' may not be the best choice. And if they can't learn to control their emotions enough to treat one another kindly, then the kids have no chance whether the parents stay married or not.