Wysteria, I recently got to this same place...got totally shut down and couldn't say a word. I longed for T to rescue me by helping me talk about my feelings for her. My problem has been that I want to talk about how I feel for her, not just anything. But I got out of this impass by backing off it and just talk about easy stuff and things I don't even care about. It's just to keep the conversation going and hope that, as it flows, I will get used to the difficult ,forbidden words gradually.
The forum here has helped me see this BTW and it's working better at therapy.