How would you feel?

Here's a little back story to my issue. My so and I both have children from previous relationships, our daughters are both named lily (his being Lillian). This man seems like he's not over his previous relationship that ended several years ago. He's been married since. 
Well, my problem is when we were laying together one night he's rubbing my belly and calls our daughter (I'm 19 weeks pregnant) Lily. Which basically means he had some sort of flashback of his ex Ashley and his first daughter. It honestly hurt me to the core. Makes me feel like this little girl isn't special to him. Should I be upset or are these hormones setting me wacky?