I need some honest feedback

LONGGG story short.. my gender reveal was destroyed. I wanted to be nice and ask my boyfriend’s mom to get results & plan it and she was so excited. As was I, I have only been with my boyfriend for 9 months. we are due with our first in March. I wanted to have it build some sort of relationship and I saw how happy it made my boyfriend. Well, it got bad fast. First she planned it and I asked her to switch the day because she set it for a day my family couldn’t attend. she refused. Called us the day it was planned for and everyone was there even after we repeatedly said we aren’t going. We canceled it weeks prior!!!!! I eventually caved and said fuck it let’s go. We get there and as I walk up with my other children, there’s blue confetti everywhere. That’s how I found out I’m having a son. Long story short I’m upset and haven’t wanted to speak to his mom at all. He’s not mad. He just thinks it’s no big deal. I think that’s insane. And even worse not one person who was there in his family even felt bad. I just stood in the corner baffled. Opinions?