My other question for all is: Now that I have dropped this bomb, how should i be acting around her, demeanor-wise. I didn't feel like last night was staged or affected or faked in any way-- i really was bothered and hurt that she didnt or couldnt say those words "Im committed" even as she tried to imply that she was, and I really felt like i didn't want to "be" with her in the MBR.
I'm sorry it did not go better for you. I really don't think you need to initiate another talk. I know you want to.......but you are too frustrated and upset. You first need to step back and cool down. She said everything you predicted she would say, so don't push for more talk.....at least for a few days.
As to how to act around her, I think you should be quiet. Maybe get out of the house and give her space for a few days. See if she approaches you with more than she gave you in the talk. If not.........then you can decide the next step.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!