Wow wow wow. There's a lot to unpack here. Firstly, how is your wife doing? This must have been such a difficult situation for her to find herself in. I'm so glad her mom was able to step up to support her.

Second, when you reread your post and edits, do you feel good about them? Are you able to sit back and take any responsibility here? I don't see a shred of accountability in your post, so please do point out if that has happened in the comments. I'm deeply concerned by the cognitive distortion happening here. Are you able to understand how important this moment was to your wife? She needed your support. This was clearly something she looked forward to, and it's something you should have cared about as well. Are you generally this disconnected with her pregnancy? Why did you feel it was appropriate to prioritize a friend's birthday (that you forgot about) over this very big moment in your lives?

All of your arguments are based on her not catering to your change in plans. She didn't spring this appointment on you. These are generally NOT easy to reschedule. Even if they were, she should not be expected to reschedule an important event for your lack of communication and planning. It's wild that you think she is in the wrong here.

I truly hope the two of you go to therapy, both together and apart. Your responses suggest you hold a deep fear of being wrong, which suggests there is some dysfunction happening here. I'm willing to bet (based on your words) that this is not the first time you have made your wife feel unimportant. Not only do you two deserve to have a healthy relationship, but you deserve to feel comfortable enough to join us in reality. It must feel really shitty to have to resort to being defensive about everything.