Parents: help me parenting while separated (2)

[Ripe]

Great news.
As far as the doctors can tell, my son does not have any physical brain damage, so the condition most probably is treatable with medication

I was just over the phone with SBTXW and she was telling me all about the visit to the doctor.
And then she told me her birthday is this Saturday and that she is going out with friends for dinner.
I though she was going to ask if I can stay with the kids - thing that I would gladly do - but what she said was that she was going to have lunch with the kids and invited me to join then.
This caught me by surprise. I thanked the invitation but declined it.
STBXW became visibly upset and said she needs to have a talk with the three of us. I asked her if she could tell me in advance what about but she replied no.
I didn't really know what to do with that invitation. Will now sleep on it.