Commenting on whether or not the lady was using him - probably. If you have a significant other, such as her boyfriend, there’s no way you wouldn’t think - ‘hmm, maybe I should tell my boyfriend so that there’s no misunderstandings’. Especially because of the way he acted - he doesn’t seem like the type to be casual about her hanging out with another guy. And with how callously she brushed him off, despite being considerate enough to lend her notes to him in college? Yeah, she probably knew that he at least had developed some sort of attachment to her, but she ignored it in favor of having some fun.