Oh, my (((marshmallow-friend))), I, too, love you!
The support here is what you need and you are only human to care and have these feelings of sadness and remorse...
Sure, you made choices... but in the end, it was your girlfriend's choice... as sad as it was, it was right for her

I hope that you can take your wonderful memories of her... look at her pictures, listen to her favourite music and mourn your loss with gratitude for having had her in your life. Yes, it was far too short... disease is ugly and cruel. Her memories will last forever.

I feel so sad for your pain