Limerence and adolescent "crushes" have similarities, crushes are typically of much shorter duration. Limerence can be consuming like an obsession, with constant thoughts about the Limerent Object (LO).
A Limerent Event(LE) can last for several years. I've read that the average LE is typically 2-3 years.
My current Limerent Event started about 7 years ago. Having No Contact(NC) with the Limerent Object reduces the intensity, but Limerence can return if contact is resumed.
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Limerence | Psychology Wiki | Fandom