Letting go after a relationship is definitely hard. There's the actual breakup, which is always always difficult. Then you have the Facebook relationship status change (let's face it, changing that little box to "single" is a big deal). And breaking the news to friends and family is utterly dreadful.
Finally, there's the post-breakup etiquette and the splitting of stuff. But what happens when you've given away more than just your heart in a relationship? Like, say, you gave away a kidney?
True story: A British woman donated a kidney to her ill husband a few years into their marriage. That's selfless love right there. But then he allegedly cheated on her, they divorced, and now she wishes she could undo the entire organ donation. Sorry, sister, I don't think that's going to work.