need to know whats wrong with her

Even if the did have a horrible marital relationship, the kids aren't supposed to be a victim of it. Anonymously send a social worker at her house and it will fix her mischievous and obnoxious brain cells. Or make an anonymous call impersonating a social worker from the kids school, reach out to both of her parents and tell them that their kids are acting weirdly at school, and their teacher is afraid that there might be some kind of child abuse involved.

I can never imagine of reacting badly to my kids when i am having issues with my hubby. Kids are kids, and a parent's relationship with kids should be independent of what his/her relationship is with the spouse. It's that simple!