I'm sorry you're struggling with this. I'm certainly no authority on fetishes (or anything else either for that matter.) But my understanding is that, since most fetishes are considered to be mostly harmless, there's not much research that has been done with regard to them. And, as a result, I don't know if anyone would be able to say why you are having this experience of more short-lived fetishes that come-&-go. It's not an experience I have had. Perhaps there will be other PC members who will have had some similar experiences who can share their insights.