I think a lot of the problem is you are confusing your ex. One minute you want to feed her cake and play happy family with her and the next minute you are ignoring her texts.
You have to decide where you stand. You are obviously not detached because you spin almost daily now. The best way to detach is time, space and stop the Intel BS. Kids finances short answers. She will get the hint eventually.
The longer you try to play happy family the longer it will take you to detach and you will suffer.
