He might show disappointment on the gender

Tomorrow I go for my anatomy scan and my boyfriend is going with me of course he has 2 girls already and he’s really wanting a boy. Me on the other hand, I don’t care rather it’s a girl or boy, but I’m afraid that if it’s a girl that he will show disappointment. He has already made a comment like “if it’s another I’m getting snipped”. And anytime he mentions our baby he says “our son” so I really feel that he will ruin my mood tomorrow if it turns out to be a girl. It’s my first experience and I don’t want to see him have a long face. Should I just go without him?