Am I being jelous or was this girl ridding it in my face, and was my voice one playing dumb?

Okay so today me F(27) and my boyfriend M(29) were finally out at a big festival party with music and some new friends. We meet up with a group of people and amongst them is a couple I didn’t know but my bf knew both of them, let’s call them Amy and Pedro. Also the brother of Amy was there and he used to work with my bf so they’re pals.
I get along like a house on fire worn Amy and her brother were dancing forever, but mind you, not once does she strike up a conversation with me.
Then my bf approached me but she interferes and continues to talk to him for over half an hour, touching his chest, arms, hips, stealing his sunglasses and hat.
I clearly eventually look annoyed so her BROTHER, yes her younger brother comes to tell me this is normal she tends to be super flirty.
Eventually I snap and walk away. I talked to Amy after and told her I’m not mad at her at all, and we were (maybe?) okay.
I’m just sad and angry and disappointed that my boyfriend didn’t draw a line. I feel like if he really loved and cared for my feelings he would have taken them into account, right?
Or am I really crazy…