We all know that this is hard- I have had people fold their tents on my sitch as well. The point is you will go through all sorts of feelings and emotions- you cannot let her see them- it's a guarantee that she has already heard and thought about EVERYTHING you have to say- there is literally NOT A SINGLE NEW statement you can say to sway her.
That being said-
Remove yourself from her life- and start to live again. Don't look back, dont get reeled into "why, what if, etc."
WE HAVE ALL BEEN THERE OR ARE IN IT NOW- myself included.
Do not spend time w/ her, keep busy, do not call or text less its an emergency reg the family. Do not pressure or pursue- just know that you will be OK w/o her, accept it as best you can and LIVE.