J.S.
Unless there was something specific in your divorce he has no right to add limits. My ex tried stuff like that, I just ignored him. The only time I was ever concerned was when he started interrogating the kids and then I explained that the language of the decree does prohibit him from doing that.
I can tell you my ex was a cheater and never dreamed he would be the one alone. It was that that drove his behavior, not any love or concern for me. As he said do you know how much it hurts me that you are happy and I am alone? I wanted to ask him, do you think I care but I didn't. I fumbled through it but I tried to be nice.
Fact is you have every right to date and he needs to get over it.
Not that you live in Illinois but in light of Barb's response I felt I should explain first right of refusal. That does not mean if you go to the store and get a sitter you must call your ex and ask him first before getting a sitter. The time period, per Illinois, is four hours or longer. Per my decree from Missouri it is set at 10 hours because my ex is a pain and if I want to hire a sitter for work I shouldn't have to deal with his games.