Update - therapist and child-centric second fam
I posted that in a previous session my therapist made an aside about children coming first in a second family. Today was my next appointment. I led with that comment and didn't give her any leads like "so did you mean X".
She made a statement that in a first family the couple is the "we" and the children exist and are part of that "we." In a second family the bio parents are still the part of the "we" the child identifies with and they do not see the stepparent as part of that "we." By default in most second families since all parents need to get along well, and probably the children need to see the stepparent as part of their lives from a very early age for that person to be incorporated into the child's "we." And it's by default, and not ideal or sometimes even livable. So she wasn't saying that's the way it should be, she said that's the way the kids look at it and it causes issues.
We talked a bit more. Her observation was from the child's point of view, not that parents should drop whatever they are doing with others (including their spouse) to cater to the children (or the ex).
I'm tentatively okay with it and the rest of the session. I will do another one. If she makes another statement that's similar we are going to stop and go down that road to see what she says in the moment.