Feel like boyfriend wishes he was having a baby with ex

So long story short I’ve been with my boyfriend a year and a half. He has a daughter with his ex wife. That daughter is not biologically his. It’s his ex wife’s daughter. I’m having his first biological daughter. I’m 35 weeks pregnant. Anyway we started talking about how we want to raise our daughter. And he doesn’t agree with anything I say. He keeps bring up his ex wife and how they are raising their daughter. Is this normal for people to do? Cause Im very hurt and I feel like he wishes he was having a baby with his ex wife and not me. Since he wants to raise our daughter the same way him and ex wife raise their daughter. Btw I don’t agree with the way they are raising their daughter but I’m allowing him to raise her the way he wants to.