We were young and naive. Jenny and I had been married a couple of years, and swinging was all the rage but at this stage the closest we had got was to listen to friend’s tales. This was about to change when Alan, our neighbour before we moved to our new house, came to visit us. His wife had just left him and we thought that he would enjoy some company. The three of us had gone out for a Chinese meal in the local town, con...