Do you want him to come to your therapy session?

I am having a hard time imagining how any answer your T would give would satisfy him. And I would be terribly resentful because it would take away T time from me. And if T said something to him that made me feel like she was on his side, I would feel like he had taken T away from me. I wouldn't want to see my T even empathizing with my wife around these issues. If he needs answers or validation or whatever, he needs to seek them elsewhere. Not on my T time. But that's me.

I think his statement that he "wants to know what is going on" is kind of boundary-blurring. Your therapy is about you, and it should be your call when you go to therapy and when you stop. If you want to share with him, that's fine. But he's not entitled to know anything, whether it helps his anxiety or not. His anxiety is his issue and dealing with it is his issue.

I share very little about my T with my wife. She doesn't even ask. She may or may not know that I leave the house every Thursday at 4pm to see my T (we have a babysitter on Thursday afternoons after school). I don't think I've said a single thing about therapy to her for almost a year. I remember because my T said something really smart about understanding an event with our youngest child, and I told her what T said.