Audrey Niffenegger said this quote
“ Martin said, It feels as though part of my self has detached and gone to Amsterdam, where it—she—is waiting for me. Do you know about phantom-limb syndrome? Julia nodded. There's pain where she ought to be. It's feeding the other pain, the thing that makes me wash and count and all that. So her absence is stopping me from going to find her. Do you see? ”