You are taking things very much to ridiculous extremes.
The position you are taking limits the rights of one parent to make any decisions or take any action without the approval of the other parent. You're right; I don't approve of that kind of limit. It's one thing to be courteous; it's another thing altogether to to tell Parent A that they're not allowed to have their new spouse participate in the child's life in any way that Parent B has not authorized specifically, no matter what Parent A wants or finds convenient. That's hardly fair to Parent A and gives Parent B far too much power. We've seen plenty of examples right here of Parent B's who don't want Parent A, let alone Parent A's new spouse, to have any kind of authority whatsoever, for reasons that range from none at all to ridiculous. Some have had valid reasons, but most are frankly, just being selfish. I see no reason why Parent B should have that kind of control.
It's also unfair to the child, who will end up feeling as if they are the one making trouble. Children are self-centered little beasts, are very good at picking up emotions, and generally assume that they are the cause of any kind of conflict.
I will give a prime example from my own life. When my daughter was 12 my ex's girlfriend (who worked in a hair salon) colored my daughter's hair after I had expressly told my daughter that she couldn't dye her hair. I felt that she was too young to start that cycle. When I expressed my displeasure to my ex, his girlfriend seriously apologized to me and stated she would never have done it if she knew I had said no. Her apology set a tone between her and I of mutual respect. It would have been better if she had checked with me first, but the apology made up for it.
Of course you have an example from your own life. You always do.
I stand by my opinion. I will agree to disagree.
I see absolutely no reason gf needed or needed to seek your permission. This really had nothing to do with you, at least as far as the gf was concerned. It was between child and father and what he allowed.
Her apology didnt set a tone of mutual respect. It set a tone that you feel a need to step into the relationship between dad and child and allowed you to feel superior to the gf.
Whenever my daughter came to me with something that I wasn't sure about I always consulted her father. That particular time she lied to her dad, he fell for it, and then the girlfriend believed my daughter and dad. I was really impressed with the girlfriend for apologizing.
Some of the people on these forums have gotten so caught up in legalities that they don't grasp the concept of good co-parenting anymore.
You know how my husband ended up with custody of his daughter? (and btw, I hadn't even met him yet at the time)
His daughter wanted to dye her hair green, and DH's ex-wife went up in a sheet of flame at the very idea. DH said, "Let her - she'll be bored with it in three weeks and dye it back". This caused enough of an issue that ended with DH ending up the custodial parent of his daughter. He let her dye her hair green and, as predicted, three weeks later it was no longer a novelty and she dyed it back to normal.
There's more than one way to parent and more than one way to manage a recalcitrant teen or tween. "Good co-parenting" does not always mean letting one parent have their own way.
I dont want to minimize the role of the “step” as they often become pseudo parents including fulfilling the typical rolls of parents in many ways but if there are parenting decisions to be made me problems involving the child, the discussion and decisions need to be between the parents. Putting the “step” into the fray simply gives the other parent ammunition if there is a problem and it allows that other parent to express control over the “step” (often through a subtle show of power such as you have described your situation to contain) that is improper.