My comment is very specifically about one phrase you used, and not about the larger picture with all of its layers and nuances and ramifications.

IF you knew about narcissism, you wouldn't say what you're saying. It is NOT about two people, one of whom isn't very nice sometimes and one of whom needs to take ownership. It's NOT NORMAL COPARENTING.

It's about abuse, period. One parent doesn't give a flying fuck about the kid, except as an energy supply/pawn in his power play, and the other parent, the only real parent, is also a victim.

The main thing is keeping the child SAFE. Who cares if you have 2 parents if you're dead or so damaged that you pass along the narcissism?