Please tell me if I'm being crazy

Back in highshool my boyfriend was talking to a girl he really liked. They never officially dated but they hung out a lot and they eventually just lost contact. This was last year and he's in college now, we've been together for almost 4 months. Anyway, they still follow each other on Instagram and they have a snapchat streak going. To be fair, he has a snapchat streak going with about....7 other people? He just likes to keep it going...he strangely proud of it lol. And it's not like he talks to her or anything. She doesn't talk to him. She knows he and I are dating because he posts about the two of us on both social medias. And I do trust that he would never cheat on me or anything, and he's even offered to unfollow her on stuff but I feel like I'd be the controlling girlfriend if I asked him to remove her. But I still feel weird about it because, I guess, their lines of communication are still open? Does that make sense? Also I feel like if I still had a way to communicate with my exes he absolutely wouldn't be okay with it. But she's technically not an ex girlfriend. Just an...ex...almost girlfriend. I don't know. Is it completely irrational hat I feel this way?