Hi tangman, you have gotten some of the best advice from PDM and others and it sounds like you really are a good friend to her. I am sure that she doesn't realize just what she has in you. If things should suddenly turn around and she wants to return to the relationship with you...I would suggest taking things extremely slow and cautious. I know that you love her, but she sounds very confused and I am sure that you would only want her back if it were for the right reasons. You deserve more than to be a fall back relationship because she finds herself in trouble or lonely at the moment. There can be a lot of repercussions to the lifestyle she is leading right now. Good luck.
