It's not as if she had wanted for her heart to stretch further than it was possible. It just became like that, veering off and sculpting its own mind when he paraded near her radius. A truly fascinating and tragic kind of ending and beginning.
Neither came from the same circle, or for having any reason why they collided.
All Luna knew was that her body and soul had been captured. He was the devil incarnated. So, tempting. So, righteous for a certain brand of people. And for Luna?
He simply was Tom Riddle, the boy who stole her heart.