BigOof, not sure if you've read any posts by member Livednlearned, but she had an experience where her son's PD dad would tell her son "Mom loves the dog more than us". Sounds just like:
Anything that represents that even the slightest risk for the child's love toward pwBPD and pwBPD takes the nuclear option.
Agreed. There's no room for any devotion and loyalty except towards the PD parent (or, in our case, the "solar system orbit" of uBPD mom and uNPD stepdad
)