Here is a (somewhat related) instance of what you are talking about: A New Mexico Resident drove for 11 hours to break into the home of Gavin Free and Meg Turney, with intentions to kill Free [0]. It seems he became obsessed with Turney and wanted Free to die "alone and without children". Obviously there were other mental health factors at play and it wasn't just "youtube fame did this", but it is a case of this largely one-sided relationship-dynamic.

[0]- https://www.nbcnews.com/news/us-news/new-mexico-man-dead-aft...