HT, I think you need to pose that to her and see how she responds:
"I'm not content to just sitting around waiting to die. I don't want a girlfriend who waits at home for me while I live my life. I want someone to live life with me. Together."
This is very eloquent, straightforward, and clear, and, it bypasses the rational side of things, so to the extent that she is incapable of reason, she might still be capable of comprehending your message in this form, because it is unequivocal and poignant.
If she does not respond to that (and, THAT is way more important than the calculations about wages vs. coupon savings), then I do not really know what you can do.