Feeling a little insecure

Kyla

So my boyfriend has a girl best friend and I’m totally fine with it but I just can’t help feeling like I’m second to her. For example we could be on FaceTime and she would call and he’d say “hold on my best friend calling me” or even she’d text something and he’d be like “hold on my best friend juss texted me” and earlier today I hung up with him because he told me she’s going through something and ik any moment she would call and he’d hang up with me for her. Idk why I feel like this because I know it isn’t like that between them. Any advice?