Is it normal to be jealous of other girls in your boyfriend’s life?

Like, I completely trust my boyfriend and I know he would never cheat on me. And yet I still get a little jealous about some girls he talks to. They’re all just friendships and it’s not like he flirts with them or anything. It’s just like he will casually bring one of them up in conversation and I just feel like I little ping of jealousy in me and I don’t really get why. And it’s only with certain girls.

One of which happens to be his best friend and he admitted he used to have a crush on her in the past but she rejected him and he accepted that and moved on and they’re just friends.

And like I’ve met her too and she’s super nice and like I know I have no reason to be jealous of their friendship, yet I am???

It’s so frustrating because I wish I could just not care and not feel that way, but it’s like I can’t help it.

Any advice?