Search Results: signs of cheating in a relationship

I sit next to this guy in one of my classes. He's very attractive and very nice. We usually chat before class and stuff. We are also doing a semester-long group project together (with a few other people) so we exchanged numbers. A week ago, out of the blue, he texted me and said that he hoped I had a nice day. I was very confused, wondering if this was flirting or if he was just really friendly.

So I respond back, and every since then we've been texting. I've never instigated the texting, it's always been him. He texts me after our class together and tells me he hopes that I have a nice day. He's told me that I looked nice, sent a couple winky faces, and some other various flirty texts over the weekend. All signs would say that he likes me or he's interested.

But then I go look him up on Facebook, and there's another girl in his picture. Turns out, she's his girlfriend. When I click on her profile, it says she's in a relationship with him. I am beyond confused. I feel really uncomfortable now knowing some of the flirty things he's said to me.

I see a couple of potential things going on here. They either broke up and never changed their profile pics or status, he's just abnormally friendly, or he's sort of cheating on his girlfriend with me.

What am I supposed to do about this? I don't want to be the "other girl" and I'm not sure I want any sort of romantic relationship with this guy.