Then it gets to the point where it's not fine. The fact that nothing will happen starts to genuinely hurt, and the fact that even if something happened it couldn't last hurts too.
You realize that he's nice to you because he's supposed to be. If he's flirting, it's not intentional, and he probably does it with every girl. He doesn't like you anymore than he likes anyone else. You're becoming annoying with all the visits, you just know it.
But it's still so much fun! When you're actually there talking to him, he'll say something that lifts you up and gives you confidence and you're back to square one.