So... my experience is that "demands" from an ex are often a test. I don't know much about your ex, but I know with mine, it usually went like this:
He would say "I need to get the kids later on Friday because [reason]."
If I said "sure, no problem" -- the next time, it would be "I can't get the kids until Saturday morning because [reason]."
And if I agreed to that, he would try to shift things around even more.
I finally put my foot down and said "Listen: My children are always welcome to be with me. But if you want to be a parent -- you need to be a parent. Not just when it fits your schedule or it's convenient for you. Either you stick by the agreement, pick the kids up and drop them off as agreed upon, or we can renegotiate the custody."
Requests or nice "asks" are OK between parents, I think. But when an ex starts dictating to you, or making demands, they're way overstepping -- and to me, it was like another way of trying to control me and keep pulling my strings.
Is that sort of what you're talking about?