My Child's Father

So I have a 4 year old daughter. Her father and I were married for only 7 months before we had separated. He was in another relationship for 3 years, they also had a child together. They are no longer together anymore, but she still acts like she is a mother to my child and I don't like it. I just don't know what to do? Ever since they broke up he is always still doing things with her and both her child and mine. When I want to see if he wants to take our child to the park or whatever just so our daughter knows that her father and I can be cordial something always comes up. He has another girlfriend and I even asked if him and his new girlfriend wanted to meet me there his response was no. Not only that but when I want to have serious discussions about our child it's like hes in a hurry to leave after picking up our child for his week. I just don't know what to do anymore. I feel like I'm just overreacting. Just any advice would be appreciated ☺ I just feel like he doesn't really care about what I have to say that involves any concerns about our child. TYIA