So I have this problem I need advice on. I'm a girl and over this past school year I've gotten close with one of my male classmates. We are good friends, and that's all fine and dandy (although you say guys and girls can't really have a strong platonic relationship, which I feel is kind of true). But I feel like we unintentionally act like more than friends. People have mistaken us as a couple before. For example, one of our teachers (who had been teaching us for months) thought we had been dating all along, before we had to correct him. We always seem to be working together on the same school projects, hang out all the time, sit next to each other in class, and even unintentionally have the same matching notebooks (down to the same colour) in our classes (which is pretty strange).
I know what you are thinking. "Whoa whoa whoa. hold up, how are you guys not together already, or not at least secretly pining after each other?" Well, I have no intentions of dating him. And although I'm not completely certain, I'm pretty sure he has no intentions to be with me either. In fact, he kind of has a thing with one of our other classmates (this is a fairly new thing). But I'm beginning to think our friendship might be getting in the way of that.
So I know that this friendship is not normal. My question to you is how can I make this friendship healthy? And what should I do to not cause problems with the classmate?
For starters, Sparkler, I don't actually think that guys and girls can't have strong platonic friendships. It's totally possible for a guy to just be a platonic friend, in the same way that it's possible to balance a dog biscuit on a dog's nose without the dog immediately eating it, and then eating all the other biscuits, and then eating all the foil out of the garbage, as is his nature. I'm exaggerating a bit, but only because I usually talk about this in response to questions like "Is there any chance this guy likes me even though we're technically just friends? By the way he is in love with me and tries to kiss me constantly. Thanks." The study I always link to doesn't claim that platonic guy-girl friendships are impossible, just that guys are more attracted to their female friends than the other way around. It also found that guys would be more willing to, uh, (consults list of PG phrases) Do The Sexytimes Upon Them. But that's also a thing that is just generally true of dudes; they are more broadly receptive to hooking up in general, no matter whom it's with.
Anyway, the point is that platonic friendships are fine and good and definitely possible; you just need to be aware of where both parties stand. And while we're on the subject: every time I get a question like this, and the LW says she's not interested in the guy, I have to arch an eyebrow and go ". or ARE YOU?" because then if I'm correct it makes me look very wise. In this case, I ask because you listed several reasons that you have no intentions of dating him, but none of them were "I don't like him in that way," which makes me suspicious. If you actually secretly do want to pursue something with him, that is the subject of a whole other post. If you do just want this to be a solid platonic friendship for now, then read on.
If you consider the tendency for guys to be attracted to their female friends, and add to that the fact that guys assume that even non-flirty body language is flirtatious, then the most important thing here is not to lead this guy on, at least not intentionally. If you genuinely don't mean to pursue anything with him, then be careful about doing things that imply the opposite. Here are some general suggestions.
Put yourself in the girlfriend's shoes. I don't know how flirty this specific friendship is, but sometimes the flirtiness is really pushing it (yawning and pretending to fall asleep on him, jokingly calling each other "beautiful," getting ironically married, etc). Consider what would bother you if you were dating a guy and apply that same standard here.
Don't indulge his flirtiness, either. If he does something super flirty and you giggle and reciprocate by flirting right back, he will absolutely take that as a sign that you want this friendship to be something more. Whatever level of closeness you currently have is fine, but if he seems like he's trying to escalate things, he probably is.