Oh, you never know. If the girlfriend goes off to a different university far away, and glasses-girl and boyfriend end up going to the same university, ya never know what might happen, particularly since their interests are more in line with each other than the boyfriend and girlfriend.
But what makes me wonder the most is why didn't girlfriend go with boyfriend to that exhibition? It's not like she couldn't go to Kanazawa any old time, and with her boyfriend to boot. Well, if she did, I guess boyfriend wouldn't have been able to progress his relationship with glasses-girl.
You would certainly think that would make sense, but this is a shoujo romance so the authors feel compelled to create the opportunity for love rivals to show up while the significant other isn't around.