Hi Wrkn, It sounds like you are trying to make sense of your SO's behavior. Let me describe mine: Believe it or not, I know the EXACT tone you describe and those condescending comments like the back of my hand. I've been living with them for over 20 years (we are finally getting help recently).
My wife talks like your SO... and I think it has to do with her childhood: She has an overbearing and controlling mother. Her childhood was without compliments or positive re-enforcement. Even to this day (we are almost 50), her mom plays serious head-games by discounting her daughters emotions and feelings. -- it's very sad. It took me a long time, but I can easily see how my wife's upbringing shaped her today.

I'm glad you guys are seeing a therapist now, before going further.
Good luck with it and hope you get what you want/need!!!