My (21f) bf (20m) has been texting his female friend everyday more than he texts me, he says he’ll stop but I still feel uneasy, how to stop?

My bf has a friend before he even met me. I wasn’t concerned bc I think men and women can be friends (even tho he has told me they cannot). He told me she wasn’t really a friend, more of a friend of a friend, just another person in their friend group and that he never really talks to her. Well I’m find out I guess he meant talk to her in person bc his chat logs say that he talks to her plenty. Probably like 50-100 messages a day. We might have 30 on a good day. He’s been texting her every day. I looked at the messages (we allow each other to snoop lol) and they’re all fairly innocent and I’m not concerned with him cheating or anything. But when I asked him about it he just said she sends stuff and he responds, but tells me that he will stop sending her as many messages since he doesn’t want me to feel uncomfortable and that he would feel uncomfortable in my position (if I texted a guy that much). I’m super insecure about this and it doesn’t help that the friend is extremely attractive and hangs at his and his friends house every day. She can’t drive so he gives her rides all the time (he says only with other people in the car). I feel like I don’t have anything to worry about, but there’s just a pit in my stomach and it makes me feel bad. How does a person get over this? I’m trying to befriend her to remind myself she’s not some bad person trying to steal my man or anything but I guess this event has kind of put a bad taste in my mouth. I think she’s a nice person, and I don’t want to be the gf that says you can’t talk to this friend you had years before you even met me. Idk if their relationship was like this before. I know that he never really talked to her at all when we were living together over the summer. So idk why he’s started talking to her so much now that school has started. What do I do? Is there anything comforting someone can say? I would like to get some advice before I talk to him as we already addressed it and he says he’ll stop. I feel bad having these feelings and I just want them to stop.