I just wanted to say that I agree with Kim...
I think many people say they "love" Declan because they see in him a kind of ideal. He might embody the perfect friend or boyfriend for certain persons. And I agree with Kim it's harmless to fantasize over this ideal through a real person... at least as long as you don't mistake dreams for reality and hurt this person, or forget to live and hurt yourself.
At our own and common levels, we might have lived what Declan lives once in our life. Have you never been in a situation when a person saw in you what she/he wanted to see... and not the real you ? Have you never had the feeling a person "loved" you for your talents, or your kindness, or your look... or some other reason... but not your all inner being, because indeed she/he did not really know you ? And indeed sometimes because she didn't want to really know you, prefering to love his/her ideal person through you until you shatter the dream by doing something that wasn't to his/her taste? I did. And what I felt for those persons who fantasized over me was just compassion. Because I knew they followed a hopeless quest, as long as they would not understand what they were searching for was inside them. I did not feel guilty. But that makes me felt very alone in a way.
I cannot really imagine being in Declan's situation. I just know I wouldn't exchange my place for his...
And concerning his grilfriend... from what I know, the person my loved ones choose were always very different from what I had envisionned for them. So, the future will tell, but you might be surprised by Declan's choice. But this is not important, what counts is that this person will be the person he would have chosen. I don't really see Declan with someone from a upper strata of the society... but that will be up to him. I never really thought about it, but I think I just see him with someone as strong as him. Someone who will not live her life by substitute through him. But after all... I don't know him at all. So he might want something else.
Well, all that just to say : I hope that people who are longing for Declan will find what they're searching for. It's true that Declan seems an adorable person. But you don't really know him (who can say that he/she knows someone anyway?). The world is full of very kind and adorable persons whith whom you can have a very deeper relationship. To whom you can write everyday or called for hours... sharing a true friendship with. Just open your heart and take great care of the persons you are with. Everybody deserve to be with someone who really care about them, and only see them as the most important being in the world.

