Fifty Shades: what do Christians say about Sex? 

If the apostle Paul was not married, how can we take seriously what he said about sex?
I do not think one needs to be a practitioner of something to have wisdom about it. Indeed, sometimes, a little distance and dispassionate objectivity can be a good thing!
Also, perhaps more importantly, Paul was inspired by the Spirit as he wrote. Paul’s words are God’s words to us.
Finally, Jesus wasn’t married and neither did he sin. Should we not accept his teaching on marriage or on sin either?

How do other Christians manage their TV viewing, in the light of the points raised in your talk? So many of the dramas, comedies and movies I watch are based on the view that without frequent, expert sex you are incomplete. That's not what I read in my Bible, so should I just switch off?

Great question. This is exactly the kind of issue that would be great to chat through with Christian friends at church or in House groups or other informal settings. It’s difficult to give hard and fast rules with regard to the 9pm TV dramas / soaps etc.. It depends on our own characters and areas of temptation.
However, I think there is a principle that runs through Scripture that what we take in, we work/live out. Proverbs warns us to ‘guard our hearts, for they are the well-spring of life.’ What we see, we cannot unsee and what we hear, we cannot unhear. Are we allowing Scriptures to inform our minds and change our hearts or are we feeding too much on contemporary culture? Are we critiquing what we are viewing or subconsciously taking it on board?
I am reminded of Paul’s words to the Philippians (4:8 f.)
“Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things.”
Perhaps we should stick this above our TVs…

It’s all very well talking about not going with prostitutes, but what about committed, non-married relationships?  Why do we need to be ‘married’ in church, when it was a cultural construct?  Bible, so should I just switch off?

Is it a cultural construct? Not according to Jesus:
“Haven’t you read,” Jesus replied, “that at the beginning the Creator ‘made them male and female,’ and said, ‘For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh’? So they are no longer two, but one flesh. Therefore what God has joined together, let no one separate.” (Matthew 19:4-6)
God instituted marriage in creation to be between a man and a woman. As I said in the talk, sex is his wedding gift, given to husband and wife to unite them in line with the promises of exclusive unity they made in the marriage ceremony.
Of course, the precise nature of the marriage ceremony can differ in different cultures so long as it consists of a man and a woman making public promises of life-long, exclusive commitment.
Statistically, marriages are more stable than ‘committed, non-married relationships’. It seems to me that this must be due, at least in part, to the public promises made to one another in marriage that act as the bedrock on which to build a stable relationship and which can give couples the platform on which to work through issues in difficult seasons.

Listen again to Paul's talk 

Jonathan Vaughan, 21/11/2015