I am not at all sure you really know what you want from him, and maybe that is the issue. I do not feel that a man should have to make a choice between his partner and his children, but there should be some sort of common courtesy when situations that place the two of you in the same timeframe come up. If my daughter was away at college and was able to come home for a few days, I would expect my partner to understand that I missed her and wanted to see her. I would want to make a change in a standing dinner in order to do so. People make changes all of the time, and as long as there was a conversation in place, I see nothing wrong with that.
I am on the outside looking in on your relationship, so I knwo I am only seeing a shadow of what the two of you are experienceing, but with the post I quoted I still wonder if you are using these examples of how he interacts with his daughter as a way he needs to change, When there is really a larger issue between the two of you. If you knew that he was truly committed to you a change in dinner plans would not matter, because you would feel secure with him. My husband seldom says much about anyone's relationships, but he has often said that there are two kinds of love: between two partners and the love between a parent and child, and that you can have both. If you were comfortable in your personal relationship with your partner you would not be nitpicking dinners he has with his daughter.
We are a blended family, my children are from my first marriage, and my husbands family does not accept people who are not "blood", so we have challenges. My husband loves me and our children, so we come first, but I have never made him choose. He always visited his family, took his nephews to games, etc whenever he could. I did not join him, and that was fine. Sometimes the occasions he was with them could have been difficult, but I figured that the less pressure I placed on him the better, and honestly that was the best decision. He was not given the same courtesy from his family, and anytime he was forced to make a choice he did, and that did nto always work well for them.
Now my neighbor had a blended family, and she and her husband never managed to agree on how to handle the adult children and the grandchildren. It was always "I am your spouse, I come first" with the kids being treated like intruders. They are now divorced. She told me I did not understand, but I really did. He was just not committed to her, she was a convenience and he was not going to be inconvenienced by her family, not one bit.
Your posts remind me of the two of them. A lot.