I've never had a partner pass away while we were together. My first boyfriend died in a car crash seven years after we broke up, but we were still on good terms and saw each other occasionally. It still screws with my head a bit that someone I was intimate with is no longer with us.
My parents had been together for 26 years when my dad died after a lengthy illness. My mom passed away suddenly and unexpectedly 4 months later. There was a legitimate medical reason she died (pulmonary embolism), but a lot of us around her feel like she died of a broken heart. It's sad, but it happens.
My grandmother, on the other hand, lived another 26 years after my grandfather died. I won't say she completely got over it, but she carried on and lived life to the fullest.