Words hurt...

So my fiancé and I have two kittens. They're still young so they like to hit start meowing in the middle of the night. He kept getting frustrated with them and our male cat kept trying to get into the fish tank. So he picked up our male, smacked his butt and told him no to teach him not to do that. Well our cat kept trying to do it and my fiancé kept smacking him and finally put him in the kitty tent and then he started meowing a lot. I started getting upset because I could tell how angry he was getting. As a person who was smacked a lot as a kid when I didn't deserve it, this really bothered me. I confronted my fiancé about it and his was response was that kittens are like having kids. Which to an extent, I agree. But I told him that I don't like the physical punishment and that if a kitten is gonna cry, they don't deserve to be smacked for it. I understand he was annoyed and we were trying to sleep but still. We started arguing and he essentially told me that we shouldn't have kids and he hopes I never get pregnant. That really hurt me. I want to have kids one day. It's still bothering me but if I bring it up, it's gonna be another argument. I know he doesn't want kids. And he knows I want kids. Most people would say that we aren't gonna work out because we both want different things, but we've been together for 3 years and I don't want to be with anyone else. It just hurts that he'd say something like that to me.