After refusing to Facetime last night ("I didn't charge my phone, don't worry about it), she took until 10AM to ask about S. I was scolded for not offering up info. You know, like a H would do for his loving W. She says she does a good job keeping me informed, and I should be a better communicator. I said I always ask about him, his day, what he ate, Facetime in AM and PM, etc and whenever she asks I offer similar info. I think that's a good job of enforcing a boundary? Info will not be offered, it must be requested. If you want instant info, you can come home. Otherwise, WW can't play family and get constant updates. I know it's something I HAVE to keep up. She has to know what she's missing.
My suggestion is first of all, stop allowing her to scold you! However, you need to bear in mind that you don't get to scold her either. The next time she starts in on you, stop her immediately. Tell her you are an adult, not her child, and you will not be scolded by her. If she continues, you hang up the phone and refuse to talk to her any further that day/night. (That is an effective boundary).
You can go even further by informing your W that as a separated couple, you are not required to play family with her (and use those words). Tell her that you will not be giving her updates throughout the time you have your son. Tell her the only time you will contact her will be if it's very necessary. (But bear in mind, it goes both ways). Stop giving her cake to eat.
She has given up her rights to know what you do in your private life. Stop telling her what she wants to know. Give very vague answers, as if she's a nosy neighbor.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!