I believe this is definitely true and in glad research is beginning to back that up. When my grandmother passed away, I am certain that my grandfather died of a broken heart and it was only 7 months later. The routines and genral rythm of life is completely thrown off when you've spent ever hour of your life with someone for the past 60 years and all of a sudden that person is no longer there. I can only imagine such pain with comparisons of breakups, and I'm sure it's a far worse situation.
I appreciate the way you dove into such a topic, very interesting. As always, I enjoyed reading it and it got me thinking, thanks!