Why am I so in love with her, and what can I do about it? She and I have the most amazing relationship....?

Here's a story for all the saps out there (I say that with respect :) ) Its a clic story. I'm just about 18, she turned 17 recently. She lives right down the street, and more often than not, I'm at her house. I can walk into her house without knocking and if she's not there either her mom or her sister or her brother will be there and they treat me just like family. Out of all of her incredible traits, she has a large flaw: She is dating an idiot. (PS this sounds like a corny love story I'm making up but you've gotta just believe me) He and she have gotten together and broken up at least four times, honestly I've lost count. Everytime things go sour between them I'm always there for her, for comfort, for a shoulder to cry on, and for a listening ear. I know she appreciates it, and I feel tremendous satisfaction in helping her feel better, but then she goes off and just starts the whole cycle over again! After this most recent breakup, nothing changed between them. They just keep acting all desperate for each other and romantic. I'm not being biased, either, he is just COMPLETELY WRONG for her. Everyone sees it. He is whiny around her, awkward, annoying, and frankly, a wimp, ask anyone. I DO NOT KNOW why she still likes him. Now you may think "Ok kid, you're hurting yourself, find someone who appreciates and likes you back". But here's the thing. When she isn't with him, and specifically when its just me and her, we connect like magic! There is something between that just makes us 100% compatible, I have talked about it with her. She agrees that I'm 10 times better for her, (her words) and even said that she really shouldn't be dating him, that it goes against her common sense. THIS IS WHY I DON'T UNDERSTAND GIRLS. I think me and her in all honesty would be entirely happy if we got married. I have an endless supply of affection for her, and maybe its the same for her, I dunno. While this boy sits and whines and makes her sad and angry on Valentines Day, I buy her her favorite little raspberry chocolates and a card. I sometimes buy her chocolate when she just is having a bad day (often because of her stupid boyfriend and PMS and all that stuff I am so glad I don't have to deal with). It is all because I care SO MUCH about her, not some petty obligation. I'm making her sound bad but don't you dare think that about her, because honestly she is only dumb when she's with him. If you're still with me this far into my little narrative, seriously thank you for reading, I'm almost done. Here is this last recent development. She and her boy are unofficially dating again, they spend time together, hold hands, maybe kiss I really don't know what they do, but they're "together" again. Stupid. I don't really pay any attention because its not new to me. So me and her (just me and her) are going to watch a movie with a couple of friends we know, but her boyfriend doesn't. We get there and actually I was the only boy, which was cool and weird and the same time. So naturally the four girls who are there decide on watching a chick flick, which I was all right with, if it means I get to sit next to her. Right in the middle of "How to Lose a Guy in 10 Days" she leans her head on my shoulder, to get comfortable or to snuggle I dunno, but seriously, I was in heaven; I could not have been happier! Then she throws a pillow into my lap and lays her head in the pillow, and puts her hand up onto my leg, like you would if you were sleeping, but also kind of like an invitation, and I took it. I laid my hand on hers and sort of stroked her back with the other. It was an awkward position for me but honestly I didn't care! She had never done anything like this before with me, EVER. And the best part was she didn't flinch away or anything, maybe she even liked it, I dunno! I felt like the luckiest guy in the world! The rest of the movie party and afterwards was awesome, we got along so great like we always do and I fell asleep smiling huge. :-D Ever since she has changed a little with me. I was giving her a hand mage (I do that sometimes when she gets particularly bad headaches) and her fingers seem more inclined than usual to curl over mine as I'm working on her hand. Its just little things like that, and it feels like there is a small hint of romance in our rock solid, amazing friendship that we've built for three years. Unfortunately she still totally acts stupid for her boyfriend, totally different than anytime when she isn't with him. So now I don't know what to do, because we sort of snuggled (loosely defined, and I feel silly for calling it that, but that's what it was pretty much) but she still has a boyfriend; and its not me. And I'm afraid it won't ever be me! If you're still reading this you have my sincere thanks, please give me your honest opinion. What do