One of the things that i found surprising about doing the "homework" that the sex therapist assigned was how much of a challenge it was for myself personaly. You kind of think that you are not the "patient" and then it kind of turns around and bites you.
It's natural to have expectations and even trying to get the exercises done can push your buttons. I think that the therapists know this and is part of deal it may even be a large part of the learning.
I'm glad that things are going so well, just remember that growth isn't always smooth and easy but it's worth it.