So I feel like there is a 2x4 in there somewhere, but it's not clearly defined. I generally understand why the dinner is not ideal (extended time around each other, gives away some level of control/perception of control over the situation, perception that I am "available" to her), but I agreed to it to make the whole engagement more neutral (having the kids around tempers emotions, it's at her place so I always have the option to leave, gives her a sense of ease as it's in her environment).
What is the purpose of cancelling last minute? That seems incredibly immature from my perspective - not trying to attack the idea, just wanting to understand the logic.
Additionally, it seems like a couple of you would not entertain listening to her at all - what is the reasoning behind that?
