MIL in delivery room troubles.

So my hospital allows 3 people in the delivery room. I want my fiancé, my mother and my sister. My fiancé however thinks he has a say in who goes in the room. He says either him his mom and my mom, or just him and my mom. He said he will be pissed off if I have my sister in the room. And I've made it very clear to him that his mother will not be in the delivery room. And that me and my sister are very close and I want her there. And he just is not having it and thinks he can have a say to the nurses that he doesn't want my sister in the room, as in what he says, goes. He doesn't get that I'm the mother in the one birthing our TWINS at that. And that he doesn't get to choose. Am I crazy, or is he being out of line?