The culture difference is real, like who tf divorces because their kid was ousted as a bully?
It makes sense tbh. Depending on their morals two parents might disagree on if what their kid did was truly bad or not,and honestly I wouldn't want to be married to someone who thought it was ok, nor would I want my kid to be raised by someone who let that behavior slide.
In this case the bullying was severe enough that he was forced to transfer (I feel like that's a less harsh way of getting expelled) & that puts a lot of stress on the parents. They blame themselves, and then their partner
(because it couldn't possibly be my fault our child turned out this way), that leads to a lot of back and forth arguing neither wanting to admit it's partially their fault and that they collectively could've done things better. There's a good chance they had marital issues before this (which would explain the kid's shitty behavior) and this was the straw that broke the camels back.