Does an affair have to mean the end?

Does an affair have to mean the end of a relationship – or could it be the beginning of something more solid? Relationship therapist and author of the book Mating in Captivity, Esther Perel says that an affair doesn’t mean that a relationship is over, but she puts forward the fascinating idea that the cultural insistence on openness and honesty places a huge pressure on relationships themselves. It’s controversial – but what do you think?