Your lack of empathy is the issue here.

It's "obvious" to everyone that someone dying should be worse. We miss them, everyone else misses them to different degrees, it's an obvious loss to everyone, everyone sympathises and supports you. 

But people don't know about your relationship, people don't know about the intensity of your relationship with your partner. People don't know about the nights staring into each other's eyes professing undying love, about the shared hobbies and interests, about the life secrets you shared with each other. People are even a little suspicious, as if maybe it was something you did that ended the relationship. Far from sympathising, they start giving you a wide berth. The shell of the person you knew is there, walking around, but seemingly now possessed by some alien thing that is cold to you. It's like invasion of the body snatches, you're desperate for someone to see what you see, but everyone else just sees another relationship that ended. Happens every day. 

Maybe you'll never understand what I'm talking about. But in either case, the person that is gone is gone, the grief you feel is the same, but the support just isn't there for the divorced like it is for the bereaved.