Melancholy is being in love with your pain.
What this looks like is a paralyzed state of holding onto the past: repeating the wanting for a relationship (or a time) that shifted. This plays out as a compulsive reenactment of the past, replaying the pattern, clinging to and controlling the uncontrollable through re-narrating. It becomes a favorite story, a mantra.
To be fixated (unwaveringly focused) on pain is a recipe for insanity: sad or zealous, it narrows you out of wider awareness. It is more akin to suicidal self-hypnosis: replay your favorite movie until death.
In part from Julian de Medeiros