I hate having to explain changes with my sons routine, foods, medicines, drinks to my ex. I feel…

I hate having to explain changes with my sons routine, foods, medicines, drinks to my ex. I feel like he is just going to do whatever he wants any way or give to much of something or just not do what I'm telling him. I mean I try to communicate these things for my sons sake in the hopes that he'll make an effort to do his best to follow what I'm doing with him. But i know I'm just kidding myself 🙄