Gender reveal upset... Long venting post

But I am heartbroken and having a really hard time not blowing up at my husband. 

I didn't want to find out at all if the baby was a boy or a girl until the baby got here but my husband said he couldn't stand that. He also very much wants a boy. I thought a good compromise would be to have a gender reveal when I am 25 weeks along (which will be May 7th) where we would all find at a party with friends and family, that way when/if he pouted about it being a girl I would have the support of everyone else and he would get over it quickly. Yes, that is the type of person my husband is that he would pout about it being a girl but I was okay with the idea of it. Today was the anatomy scan and after he gave the ultrasound tech a hard time about not letting him know she managed to write it on a card and put it in a sealed envelope before either of us saw anything. Fast forward to the end of the appointment, my husband snatches the card and drives off. He gave the envelope back, I can tell it's been opened and he's giddy so I'm pretty positive it's a boy.    I feel robbed of a fun special really important moment and my feelings are hurt and I'm super disappointed because I begged him not to do this before the appointment. And I guess I just needed to vent because I can't stop thinking about how unfair it is but also how it isn't worth a fight with my husband.