Ooh! Good luck with it! You're really brave to give it a go, especially with your own therapist. I'd worry about being jealous of his interactions with others too - not just his patients, but anyone in the group (I get jealous easily I guess, lol!)

How do you feel about being put in a position to support someone else? That would worry me a little, I think, as it feels like an odd thing to put on you (i.e. you should be there to focus on yourself and getting the skills you need, not to worry about what's going on with other people). How is he imagining that you're going to support this other person? (I could be off-base, I have never done group therapy or a dbt class.)

Good luck with it! Keep us posted! I'm really curious to hear what you think of the class... I've had a couple Ts suggest that I go to DBT...