To me it would be logical that the mother would connect her husband's obsessive cheating and sexting with what happened to Cooper. So even if she believes it was an accident, I believe most women who would be upset enough by cheating to file for divorce would automatically blame the husband who was actively engaged in such behavior when their son died, for that death.
I reallt believe that a lot of the strange things and behaviors we've seen in this case can be explained by one thing- Cooper was not the main focus in that family. For Ross, his needs and desires were. For the mother, I believe she had raging insecurities and feelings of worthlessness and a panic about keeping her man. I think that was her focus. Cooper was just not first in their lives, IMO.
Otherwise, it is extremely natural for spouses to blame each other for a child's death, even when it is an accident or even illness beyond their control. So if there is a hint of actual culpability or negligence, that's even more so. IMO each parent had an obsessive focus that caused Cooper to be less important.
