I do hope you go back to your T and make sure that your BF stays out of the waiting room. Your T at the very least needs to know how thin the walls are. That is a really horrible thing for you to learn this way.

What your BF did was incredibly wrong. He has no right to make you feel bad about what he did. I worry that he is trying to take away your support systems by making you feel insecure about places which should be safe - and which would have been safe if he had not chosen to eavesdrop on a private conversation.

The way you talk about walking on egg shells and being vacant because you don't want to upset him sounds very much like a toxic situation. I hope you can work this out for the best. Talking to your friends, when he isn't around, sounds like a great idea.