Re: Responsibility for other people's decisions
You can't be responsible for how she feels, or for her decisions. If her attachment makes you uncomfortable, then it becomes your decision to stay or leave the FWB, or dial it back to just friends. If you're not uncomfortable, and your views are completely clear and known to her, then it is her choice to stay in a situation that won't resolve in her favor. Remind her of that occasionally, and then it is not your responsibility. She is an adult, and as long as she has accurate information, is responsible for her choices. However, as I said initially, if her choices make you uncomfortable or creates problems, then it is appropriate for you to move on.
Personally, I'd feel uncomfortable being the one who is the reason for her poor decision, and so would probably move on just for that.
Love is an ideal thing; marriage is a real thing; a confusion of the real with the ideal never goes unpunished. - Johann Wolfgang von Goethe
CELIBACY IS NOT HEREDITARY.