I was that guy for two years in college. A girl called me up, heartbroken over the professor she'd been in love with. He said they couldn't be together because it just wouldn't work. He had a wife in another state, and she, my friend, couldn't compete with that.
Anyway, I played the surrogate boyfriend for a while. I wrote her a letter saying, "We may not be in love, but for a while I can show you what love is supposed to be."
It was fine for me, but what I leared from the experience is that I'm someone who ties emotion to sex. I sorta can't help it if I start to love the person I'm in the act of mating with, continually. That's why I don't have casual sex that much, but I'm still in college and willing to try.
In your situation, just listen to what this girl has to say. Be there for her to talk to. That's all she wants. If she wants a relationship of sexual nature, she'll let you know. Until then, if that ever should offer itself, just listen. That's all some people want is for someone to listen.