So much has been written, both agreeing and disagreeing, with the concept of Parental Alienation. I may be naive and oversimplifying, but if a person was a good parent while married to the other parent of their child(ren), why does divorce (or a breakup) change that?
You have two people who have chosen to bring another life into this world. Most times, a conscious decision was made: I want this person to be the parent of my child.
After the child is born, you have two people who are both loving parents to their child(ren).
Why does that change when these two people can no longer maintain a relationship with each other? That doesn’t change the people they are. That doesn’t make them any different from the person they were when the decision was made to bring a child into this world.
Why does a divorce or breakup mean one person is no longer fit to be a parent, and have a relationship with the child(ren) who were so lovingly brought into this world?