A person grows up most the day they are forced to bury that cheerful child inside. You don't learn to dig graves through love; you learn when life forces that shovel into your hands.
Those suffering from heartbreak heal one day. The truly dangerous ones are the walking dead whose hearts are frozen, owing not a single feeling to anyone, living silently while feeling owed by life.
Do you know why a person's smile fades? Because the brain eventually learns that "happiness" is a dangerous vulnerability and self-destructs that button to protect the system.
They say "you'll forget." Nothing is forgotten. You just learn to lose the key to those old feelings locked in the furthest basement of your brain. It's still there, just rusted over.
You thought life would take lovers from you first, didn't you? Life steals peace in sleep, causeless morning joy, and that old self you used to recognize when looking in the mirror.