its an illusion created through lack of fullfilment, because you know this woman as almost forbidden fruit, or at least not in a real tangible way... (think farting terms).... then you ahve in fact put her on a pedistal... you ahve made her into an illusion of herself.
I've done that especally with relationships that never really started... tey haunt me...
My biggest haunting ended up last year, it was a situation that ended abruptly but they were in my lfe last year on different terms, I was engaging but something was causgn me to be observant in a clinical way... ie I watched him, because of the way it ended in the past.... the more I saw the more I realised that he was vry psycologically damaged... I'd made him into something he could never ever be... and I had haunted myself with an illusion of what this person is like.
I have no idea how you make this woman real, but I can totally relate... what ever you do, excorsise her from yourself is a requirment of you being able to have fullfilling relationships with other people who are real. I can give you a cast iron gaurantee, illusions and imaginary flaw free people are WAY better than real ones, they disspoint less and they they never challenge you in a way that helps you to grow... find freedom what ever way you can... good luck