Hi there. This might be a quite complicated story, but here goes...
For about three years ago, i met this extremely beautifull girl at a dating site. After we had talked for a while, she told me that she was about to delete her profile, because "she knew who she wanted", but he wasn't on this site. She also told me that she really wanted to keep in touch, so she gave me her facebook. This guy she was dating, turned up to be a real douche, and i stood up for her, and talked to her every day. After this, we built up this weird relationship, pretending to be married. As i had other girls i liked at that time, i didn't really take this too seriously, but yet again, we talked almost every day for half a year. We lost contact for a while, she got a boyfriend, and i didn't really think of her too much.
But she eventually contacted me again, and we continued to talk every single day. This time there was nothing romantical about it, as she was in a relationship. After a while she told me that they had broken up. From here on, our relationship grew really strong. She was really into me at this point, and it kinda freaked me out. I liked her, but she was moving forward so fast. After some time, we continued with this "online marriage" thing... But this time it was different, we both had real feelings for each other now. The feelings grew really strong, but we hadn't yet met in real life. It all went really well for a while, but she had gone from being the girl who missed me if we hadn't talked for a day, to not really needing this confirmation. So here i am now. She still refers to me as her boyfriend, and she still loves me, but i don't really feel like she has the same interest for me anymore.
This is where i think i went wrong; I put this girl on a high horse, gave her confirmation ALL the time. I was too shy to meet her, and she grew tired of waiting.
I dont really know where to go from here, guys... I really want things to work out with her, she is totally out of my league, but i still have her about where i want her... A couple of days ago, i recieved a message, where she told me she missed me. What do you think ? Should i make myself less available for her, make her miss me more ? How do i maintain her interest online ? I don't really want to meet her before i have worked more on my confidence and so on... You only get one chance with a girl like this, and i dont want to spoil it.
I know this was extremely compicated and badly written, but i hope there is somebody who can help me a bit here

This girls feels like she is "the one"... If anything is unclear, please ask !