In life, we don't just mourn the death of people. We mourn the death of things that don't live up to our ideals. Situations that we originally conceived of one way but ended up blind-siding us when the true reality becomes apparent.
How do you process this "mourning"? It depends on whether you're a thinker or a feeler. Everyone is a little bit of both but we all tend to have a dominant mode.
I'm a feeler. When I mourn, I experience it as a feeler experiences it. It is an acute emotional pain. I feel it from every angle. I feel it from the perspective of all parties.
My husband is a thinker. When he mourns, it is primarily on a logical, rational level. He processes it in terms of facts. He processes the "mourning" faster than I process it because he understands it on a fact-based level. He doesn't have to sort through the emotional complexity that bogs me down.
Mourning is not optimal. But mourning is inevitable.