My friends who once swore they'd never to commit a life with one person are now doing just that. I'm not sure why. Perhaps it's part and parcel of being in your 30s when the shackles of marriage seem less easy to resist.

Or of course, they could just be happy. Yet, whatever the reason, after the euphoria of the engagement comes the challenges of the wedding.

The UK's royal family is no exception. With royal heir Prince William getting married on April 29, invitations have been sent out to 1,900 guests who will watch the prince and Catherine Middleton walk down the aisle at Westminster Abbey. Among them will be 40 crowned heads, 60 Commonwealth Prime Ministers and a sprinkling of celebrities.

Family and friends will abound with a thousand people from both bride's and groom's sides. This is a marked improvement on the 30 personal guests that the then Lady Diana Spencer was allowed when she married the Prince of Wales exactly 30 years earlier.

One glaring exception this time around is Sarah, Duchess of York, now memorable for her appearances on Oprah, though initially known for once being married to the Queen's second son. As an aunt to the groom and a longtime friend of his late mother's, the Duchess was expected at the nuptials. But, years of indiscretions, not least being filmed trying to sell access to her former husband, have cost her a coveted place.

It's a story familiar to any bride and groom.

Who to invite and more often who not to invite involves a delicate diplomacy. From a best-forgotten uncle to a grandfather ostracized from the family, there are plenty of examples.