When I was about 17 I began dating a very vocal Satanist. My personal beliefs were still lined with a thin veil of Christian dogma, but I was truly Agnostic if anything. He gave me a copy of the Satanic Bible for Valentine's day and also a selection of essays by Nietzsche. From then on it was history. I felt myself becoming less and less deluded as I read on like "Wow, how could I have been so blind."
The boyfriend turned out to be a bit of a sociopath and he did break my heart into a bunch of little bloody pieces, but one good thing that came out of it was the realization of my true nature.