Actually. I HAVE been in your situache before. It's harder to "get over" this person (moreso than the 5.5 year one) because you are infatuated with him. Usually, in this stage, we tend to get a little obsessive. My current boyfriend started as a fling (oh so long ago!) and because of many complications (the major one being that he was always out of the country), stayed that way.
But I NEVER got over him. He was "perfect" in every way. Of many things: his goals, his personality, his taste in music, his physical side--and yes, our sexual chemistry was (is) amazing. His potential at being more than a fling, or boyfriend to me was sooo high. I fell hard, and it was magical.
After 6 months, I was still not over him. I wouldn't talk to him, or even see him in my desperation to get over him. Then I would get a call, or text from him, and the obsession started all over again. It was a cruel joke.
I have no idea how we get together, but we did. And have been together now, for around 2 years.
I find that if there was a reason for me to leave, or if I suddenly fell out of love with him, it would be so much easier for me to get over him. Because I've already been there, and done that. I've tried my best to stay, and dispite everything, it wasn't meant to be. We weren't meant for "forever." So it would be easier.
In your situation, however, there's that hope, that potential. And the fact that you felt that he was perfect (since you don't really know him, and see him only though rose-colored glasses) would make it harder for you to get over him.
So... that's just my 2 cents.