AITA?

Me & my child’s father do week by week coparenting. Recently he got a job where he picks up shifts and lately he has been picking up shifts as soon as they pop up on his week to have the kids. I’ve told him countless times to check in with me before accepting shifts but he says he can’t because somebody will take the shift quick. Me personally I don’t think he should pick up shifts when he has the kids, he treats it as no big deal because my sister usually watches them during the day and he says technically I don’t watch them because I’m at work but I don’t feel as though it matters because he’ll drop them off right before I have to go to work & it’ll make me late because he sends them without diaper changes and without having breakfast so I’ll have to take care of that. I told him to apply for a daycare voucher countless times and he said he finally did and didn’t get approved which I don’t believe because my sister is a government worker, makes 3x what he does & got approved for it. I literally separated from him because I didn’t get a break and now I feel like my weeks are always shortened but he’s manipulating the situation saying I just don’t want him to work or I’m being selfish but anything I do I make sure to do it on my week I don’t have them.