This audio from Capitol Hill Baptist Church (pastored by Mark Dever) is extremely helpful, better than nearly anything I have heard in American evangelicalism and fundamentalism on the topic of dating, relationships, and their related issues. If you have a ministry with teenagers, singles, or young adults, or know someone in the aforementioned group, or even plan on having children, you need to listen to this. Even if you do not fit any of the near-exhaustive categories of persons I just mentioned, you should listen to these; they are a rich source of encouragement and admonishment toward purity in these matters.
I have not listen to all of these, but here are all of the “talks” that seem to be related to the subject at hand:
Men’s Talk on Christian sexuality
Men’s Talk on Christian sexuality Q&A
Women’s Talk on Christian sexuality
Women’s Talk on Christian sexuality Q&A
Jesus and the Seventh Commandment
Does Thin Equal Beautiful?