he Duke of York, who celebrates his 50th birthday this month, is a surprisingly complex character. Despite his playboy image he is essentially a one-woman man who shows his former wife Sarah the same kind of loyalty and affection as when he was married to her. This is fortunate for her as it allows them to be together with their children, enjoy holidays as a family and share the problems of bringing up two girls – the only grandchildren of the Queen to use the title Princess – in an increasingly difficult world.    Sarah has the use of a suite at Prince Andrew’s Royal Lodge home and as they both travel so much they do not impinge on each other’s space. It seems to be an ideal arrangement, but I doubt they will ever re-marry as Sarah has no intention of returning to the restrictions of the royal fold. She is a big earner, but has always been a big spender and needs to continue to work as hard as she can.    On a post-New Year break to stay with friends in La Santera, near Gaucin in Spain, I was lucky enough to have lunch with artist Nicky Philipps, who painted the new double portrait of Princes William and Harry for London’s National Portrait Gallery. She is charmingly modest and the launch of the portrait made her nervous, as she is an artist, not a self-publicist. I was thrilled to see the positive reception the painting received from the press and next month we will have an exclusive interview with her, revealing some interesting insights into the two princes, whom she got to know over the period of a year.    As always, the fascination with William continues as he broadens his role. Of course everyone wants to know about? his relationship with Kate Middleton and whether they will marry this year or not. For the prince, the most important thing is trust, and in Kate he has found a girl who is not only beautiful but also totally trustworthy. But more important than wealth or an aristocratic bloodline (once perceived as essential), she has loyalty in abundance and a stable background of happy family life. They both know that when and if they marry their life will never be their own again; when they do wed – and I am sure they will – they have to be ready for it.    It has been announced that the Queen’s Diamond Jubilee will centre on June 2012, with a special four-day Jubilee Weekend being planned to celebrate and commemorate the events of Her Majesty’s 60-year reign. Details will be made public nearer the time. It is important to strike the right note, and of course 2012 is also the year the Olympic Games come to London. How about repeating the street parties that made the Silver Jubilee in 1977 so memorable?