I'm sorry! I think this is concern is valid and not childish at all.

You fear losing your T, and of course you do.

That would be a significant loss in your life because your T is important to you. And now T's outside life is disrupting your therapy.

I thought the whole point of the T's responsibility is to be steady and consistent, especially for people who have never had that.

The disruption is disturbing.

I hope you two can discuss it and that it works out well for you both!