Does your boyfriend have girl bestfriends?

My boyfriend has 1 super close one. Some days it bothers me and some days it doesn’t. It doesn’t help that she also my best friend. My boyfriend and I hang out with a group of friends that we mutual agree are our friends, but he’s close to one girl. I don’t know, it’s probably just me getting jealous, but it sometimes just makes me upset. He always tells me there’s nothing to worry about and that he loves only me. He’s also loving so it makes up for it. Just wanted to share/vent. I also want to see some other experiences/perspectives on this type of situation.