Collateral damage
This man made a very smart decision when his irritation at his wife spilled over to his kids. Indeed, it’ll hurt the kids when their parents split up, but it’s a lot better to have two happy parents living separately than two who argue in front of you. His mind cleared the moment he realized he was doing more harm to his kids by sticking to a dying relationship.
Now that the husband and wife are officially ex-husband and ex-wife, life is going swimmingly for the two. He was able to fix his relationship with his kids, so they’re a lot happier, too.