Parental alienation happens when your ex attempts to turn your kids against you. While you have a legal right to see them and be involved in their lives, your ex emotionally manipulates them to take them away from you by making it so they do not even want to see you.
It's heartbreaking when it happens, and it's potentially illegal. The children's best interests should always come first, and that generally means seeing both parents. Anything that gets in the way of that is likely focused on what your ex wants, not what the kids really want.
One key sign of parental alienation is when the child starts to make exclusionary requests.
For instance, maybe your son or daughter has always played basketball. During the marriage, you were their strongest supporter and you went to every game. After the divorce, you want to keep going. You do it for a while, and your ex can't stop you, but it's clear they don't like you being there. Then, one day, your child asks you not to come to the games anymore.
It's a red flag because it's such a drastic change. Ask yourself why your child would suddenly not want you to be around. Why are they really trying to limit contact? Is your ex threatening them or manipulating them to push you out of the picture?
It's hard not to feel incredibly hurt when this happens, and that's all right. But, rather than getting angry with your ex, it is time to put your emotions and energy into finding out what's going on and what legal steps you can take to stay in the child's life.