There are few books that have had such an adverse impact on my life than the book "I Kissed Dating Goodbye" by Joshua Harris. I read this book in high school and it follows the author's decision to never kiss or date a girl unless he knew he wanted to marry her. He said that in order to remain "pure" he had to abstain from even dating or spending any time with a girl one on one.
The book was recommended by a lot of people who were authority figures in my life so I read it and, as I do with almost anything in my life at that time, I went all-in on the suggested course of action.
In hindsight, I can see how many relationships I messed up, how many opportunities for real connections I missed, and how out of whack all of my understandings of the physical and sexual pieces of relationships were built on the smallest sliver of understanding.