Their romance had started in Mustique, the Caribbean island then owned by Lord Glenconner, and that was always a bone of contention between Lord Snowdon and his first wife.
According to the new book, Lord Glenconner – the former Hon Colin Tennant – had been dismissive of Princess Margaret\’s plans to marry a commoner. When Tony Armstrong-Jones visited Lord Glenconner\’s London home, the peer even made the photographer use the servants\’ entrance. Furthermore, when Lord Snowdon and Princess Margaret married, Lord Glenconner gave a spacious building plot on Mustique as a wedding present, but he insisted it was a gift only for the bride, not the groom.
As a result of the snub, Lord Snowdon spent only a single night on Mustique and called it "Mustake". He was even less complimentary about Lord Glenconner throughout his first marriage, referring to him as "s**t".
Given that treatment he seems to have got it about right.