Have read this thread with interest. The issue of when to object to something and when to step back for the sake of the child is a very difficult one indeed.
My dd has a sm and i have to be honest, I learned a lot from this board on how to distance myself from what felt to me like a major intrusion on my role as a parent. I have had to face some very difficult situations regarding my dd and her sm and I've made some mistakes along the way by reacting to things I should have let go. Similarly, I've let things go that I should have defended.
I'm grateful to this board for giving me some perspective on what is probably the most difficult thing I've ever been through.
Like a previous poster, I've come up against all manner of protests from friends and family who feel I've been 'walked on' by sm and exp, and who feel would like to have me washed out of the picture completely. I (mostly) saw it differently, ie, that i was putting my dd first etc etc. The truth be told though, ( and it took me a long time to admit this to myself) i was mostly always responding from a position of fear, rather than a total desire to put my dd first. What I mean is that my instincts told me that to protect dd I should fight my corner, but I was always so damn afraid of confrontation with exp and sm that i have let things go that I absolutely believe were not in my child's interest. I still struggle with that- the balance between defending my right to parent my child without interference against my child's right to a happy life with both parents.
The fear is not completely gone. I can't explain the fear very well, although if i had to put it in a nutshell, it stems from the realisation that if I ever object to exps demands, I receive texts and emails ( written by sm) that succinctly and articulately tear my parenting to shreds and could be written for a judge, loaded with references of their 'concern' for dd's well-being and how they are devastated that I cannot 'put her first.
These emails and texts I should add are usually over the most trivial of issues, like an ill-fitting pair of shoes, or me asking exp to drop dd off at a restaurant where we were having dinner on a sunday evening. The issue I have, is that sm is very very intelligent ( exp is unfortunately not) and the emails are worded in such a way that you would be convinced of abuse on my part if you read them. They crush me completely and I cannot - 5 years later explain why I can't let it wash over me. I just can't. And so, I usually give them what they want in order to avoid the very predictable assassination of my parenting that will follow.
I wish I had more belly, honestly. I wish that I could find my voice to say that I am not ok with some things. I havent always agreed with every poster on this topic. I recall one recently where the poster fundamentally believed it was in her child's interests to keep silent about her child being treated differently by his step-parent. She felt that a confrontation would not help the child, and yet I wondered how not defending him would help either? I also realised that I was very similar to that poster.
We can all shout about the interests of the child until we are blue in the face, but I worry so much that I have not stood up for myself and my dd enough that she will resent me when she is older. I genuinely can't see how a a child will thank you for keeping quiet about behaviour that you know to be wrong.
I realise that my point here isn't specifically linked to the op, but rather how the thread unfolded to discuss relationships between the parents and speaking up when you don't agree with something. However, the op's approach does somewhat remind me of my dd's sm, in that she also feels that she has no obligation to consider my feelings on any issue. I've posted here about the many school events that she attends ( completely on her own, not with exp) and how much I hate it. Every time I go to the school, my heart is thumping with anxiety that she will show up, clapping and waving to dd.
Am I wrong to be upset at her presence? I don't know. I feel embarrassed and threatened by it. It isn't something I would ever do- and I am not convinced that she is acting in the best interests of my child. Similarly OP, and I'm sorry if you disagree, I feel that being present at your step-child's first day is not in the child's interest either, but in your own.