"but I have noticed that I used to change myself in small ways to try and please him. I used to protect and defend him in front of others."
"I basically feel that I was always trying before - as I said, changing myself in small ways to make him happy. Agreeing, when inside I thought otherwise - as most people probably do in friendships and marriages. Now I just don’t want to do that."
I think these things are as significant as the disagreement about the baby.
I think women are socialised to be extremely agreeable and to ignore the effort that this takes. When you meet someone and you are young and energetic, you put a huge amount of effort into being agreeable - both to your man, and about your man - always presenting him in the best light, covering for him socially, as well as making sure he feels agreed with and supported at all times at home.
When you add extra pressure into the mix - like small children, let alone the disagreement about wanting more - the whole thing starts to feel exhausting and relentless. You start being aware of how much you give in return for so little, because you hit a point where you start to feel what it costs and that you have no reciprocal arrangement on all these small and constant acts of giving and support.
I think you may resent that as much as the child. you say you have accepted that there will not be another child, but still feel resentful. I think there is a part of you that has just decided: It's my turn now. Let him do the work for a while.
The trouble is that he has no idea how to do it, or what you have been doing. He can't step in to nurture your bond by giving because he never even knew you were doing it, and if he did know or understand what to do, could well find it impossible or beneath him to make that much effort.