My ex scheduled an appointment during my visitation time

I have spent and entire year getting less than 2 visits of 2 hours per week with my kids. Last week, the hearing I have been waiting for ruled that I allowed 2 out of 3 weekends plus Wednesdays from 8 to 11. I was dropping off my kids today and my ex stated that my daughters early intervention therapist had to change her appointment time. Without even asking me, my ex scheduled it for Wednesdays at 9. Right in the middle of my 3 hour visit. She is expecting me to let the therapist come to my home. I live in Pensylvania. Was my ex within her rights?