I was once told that many people fall in love not with the people they think they are in love with, but with the image they have in their mind of how they think that person is. Of course, the image is not the person, and when the person does something or acts in a way that doesn't fit the preconceived image, they get hurt, angry, disappointed. This is more common than we might think. Think of how many people are hurt by lovers without suspecting anything beforehand. Worse, think of how sociopaths can get away with so much in society. It is partly because so many cant see what is before their eyes. Charles Manson's followers certainly had a different image of Manson in their minds than others with more sense did. So I think you have touched on something more important and more fra-reaching than you may have realised.
As for falling in love with images created entirely in one's mind, I think that it's not likely, since most people want something real to attach their affections to. In sum, I agree with Geoff.