Trying for a baby with a guy who already has a kid

I am not pregnant yet, but me and my bf recently decided we want to have a child together. He has a child with his ex.

Last night we were JOKING around, and he said to me "just wait until your pregnant, then you'll really turn into a bitch and after the baby is born" and the continues on about how when his ex got pregnant and had their child she turned into a huge bitch.

I hate these subtle reminders that he's experienced this before with another woman, it's not his first child and he's been through this, i feel like he thinks I'm going to get pregnant and turn into a bitch, and that us having a child isn't special at all to him!

How do I deal with the mixed emotions of having a child with a guy who already has one?

I am so excited for us to get pregnant and have a baby I have been waiting for this for so long! I just get so emotional and sad idk what to do about the feelings cause even though I'm not even pregnant yet.

I'm sad because I always saw myself going on this journey of having a child the first time with someone who also didn't so it would be just as exciting as it is for me! But that isn't the way life worked out, which is fine, itsjust very hard for me to get past. I love his child but isn't the child enough of a reminder that he's already had a kid and done this before and I haven't... sucks