Once I saw my T’s daughter in waiting room. I knew he had a daughter and if he hadn’t told me who it was I would’ve asked. It didn’t bother me, it’s not common for him, in fact It only happened once and I’m guessing he wasn’t able to get anyone to be with her. If anything I’m glad he didn’t cancel on me, I’m sure it wasn’t an ideal situation for him. I’m guessing your T didn’t expect you to see the other person. I think it’s ok to talk about how it made you feel.