I've been divorced for a few years now, I have shared custody of my 8 year old son.

Since separation my ex is doing little things trying to pretend I don't exist for matters related to my son. Just a few examples:

My ex called the school, doctors, etc. and changed my son's address from my house to hers (I kept the matrimonial home so there was no need to change anything).

She got a boyfriend a year ago. Then I started receiving emails like "we have signing up" for let's say soccer. By "we" she means her and her boyfriend, completely bypassing my decision making power and pretending the boyfriend is his dad. She also signs him up at a location and time she knows doesn't work for me so I won't be able to take him during my time.

We decided that it was best to attend parent teacher conferences separately. At the last conference, on top my son's sheet the teacher had my ex's name and her boyfriend's name written. The teacher told me that apparently my ex had been there just an hour before and she had told her "he (the boyfriend) was his step dad so it was important she made a note".

A friend told me this petty behavior is parental alienation. She's trying to pretend I'm not relevant.