Hmm, for watever reasons, if she/he ends it just like that, maybe it means this relationship dont mean as much to her/he as it does to you. I think if relationship is important to both parties, then at least they will try their best to work things out before using last resort...
If she really seem to lose interest over this relationship, then I say get over it, not worth losing sleep over it, no?
Be grateful she didnt do so after u guys r married and with kids and fight over ur assets

But, I know easier said than done, just cheer up
