gender reveal fail 😱

Okay so I'm pregnant with #2  & my so wanted to have a gender reveal for me . All along I've been telling the techs I don't wanna know only he can . She asked if I wanted the gender of the bby on the ultrasound downloads she was sending and I said no ! The first time it was sent it wasn't on there & they just happened to send it again today .. as I scroll down there it was " it's a boy. " I already have a 10 month old son .  😩😓 . Idk if I should let him know I know or just act surprised when he tells me .. I really thought it was a girl so I'm a lil sad lol 😂