Is it strange for my girlfriend (24F) to have a male best friend (24M) who is attracted to her?

It seems they've been friends for quite a while, and this guy has a crush on my girlfriend. Although she’s aware of his feelings, she insists she doesn't have any romantic feelings for him, so she thinks there's no reason to be concerned. Nothing has ever happened between them, aside from him asking her out, which she turned down. Despite that, they've maintained their friendship. Do you think this situation is odd?