It’s the kind of “end of an era” feeling you get when you commit to something, be it a joke or a habit, or even a relationship. When you invest time into something, be that accompanied with meaning or not, you don’t want to let it go because that thing is now a certainty in your life. Taking the necklace off is removing that stability, that constant, that era. It’s deeper than you have to think about it but I hope it makes sense.