2009: Girl goes backpacking in Europe, meets boy. Lets call him John. Amazing connection.
End of summer, girl leaves. They never talked about long distance, nor did they break up. Just let the relationship fall into space.
Girl and John keep in touch off and on over 3 years.
2010-2011: Girl convinces herself John is just a fantasy greater than real life. Even if he did ask her to come back, or if she went back, it wouldn't be as good as she dreams. Gets onto a path of a new boy toy every six months, but they are never anything to commit to.
2011-2012: Girl meets... lets call him Dan. He is wonderful. Nice, caring, passionate about his work, everything you could want.

A year and a half in and living with Dan, girl is still pen pals with John. It has always just been idle small talk up until now. John has dated over the years, but his girlfriends never last long. He is still as sweet and funny as he was over three years ago. But now John is skirting on more than just idle conversation. Reminiscing about that magical summer, baiting for some sort of reply. Both girl and John never saying what is truly on their minds.

So I ask, what is a girl to do?

You still "love" an former summer fling from three years ago? You have a boyfriend of a year and a half and you still need the internet to tell you what to do? Come back to planet Earth, cut the pretentiousness out of your life (your post is filled with it) and focus on reality—ya know, your actual relationship.

I agree with slapshot.

If you are in a relationship with Dan, move in together, why would you continue to talk to John? I am not a big fan of leaving something good for something you remember as all good. When you are not with John you are not going to remember the issues, if there were any. If there weren't any issues I would guess you two didn't know each other well enough or you two knew this was a fling that was going to end so why add any stress.

Either way the thought that leaving Dan for John and that a relationship with John will be nothing but good times and fairy tales is a dream. There is a reason why his relationships don't last very long. Can he not commit? Does he get tired of present girl? It could be a number of things.