So, it looks like she has set up home elsewhere and didn't divert the post via the postal service as this can be traced and I "may" be able to find out where she is. So calculated and planned. I think that's it then. No hope.
Been there, done that. When my long-term XGF left, the first shock was her leaving, the second shock was discovering that in contrast to her words she'd planned this enough to change her D's school district before moving out. The second shock was the realization was there was no easy way out, no shortcut home.
"No hope" is a thinking error. She doesn't plan to return to you. That doesn't mean she won't change her mind. As others have pointed out before, at one point she was completely uninterested in you, then she wanted to marry you, then she wanted out. She's changed her mind before. It could happen again in time.
As a reference point, my long-term XGF and I reconciled.
