What are some ideas for how to adjust to missing out on part of your kids life?

I have 50/50 custody but it still is so hard. Today was his first day of summer camp and I don't get to talk with him about how it was. It's heart breaking.

I know I'll see him tomorrow and hear all about it but man, it still crushes me thinking about it.

(Mom isn't willing to do calls on her days and he's too young to initiate on his own)