Gollumny

Gollumny: stalking a person to steal a highly valued object, or to become so obsessed with someone else's possession that you fray with insanity (can apply to relationship stalking as well)

Derives from LOTR character Gollum.

Damn her ex is suffering from borderline Gollumny, his mounting jealousies only seem to get more tenacious and his attempts at reclamation seem more and more desperate, if you listen closely enough you can hear him mutter "my precious"whenever she is within sight.