I had a similar experience in psychodynamic therapy. My exT wasn’t totally blank slate, but I didn’t know much about her. Her affect was flat and often I’d speak and she wouldn’t say anything at all in return. I ended up oversharing because I just kept talking to fill the space and then I got super anxious about what I had shared. I finally got incredibly angry at her for not responding to me when I talked and then snapped at her about it. She promised to change her approach, she did for a few sessions, and then all of the sudden she went back to not responding anymore. I flipped a ****/we had our first rupture over this. She told me her supervisor (she was a postdoc fellow) told her to go back to the old style. I was not happy, because she didn’t even tell me she was shifting approaches. My whole therapy was ineffective with her...to say the least...I really can’t stand a flat affect therapist.