Since saying “I do”, Sophie and Prince Edward have had two children together.
Lady Louise Windsor, 16, was born in November 2003 and James, Viscount Severn, 12, was born four years later.
When Sophie first met her husband she had a career in public relations.
Shortly after their marriage, however, she took on a role as a full-time member of the Royal Family.
In this position, she has joined Prince Edward to represent the monarchy across the world.
Prince Edward is the only one of the Queen’s children that has not had a divorce.
Body language expert Judi James explained why their relationship may have seemed unlikely to last.
“Of all the Queen’s children, Edward was perhaps the one least expected to make a strong, long-term marriage,” she told Express.co.uk.
“Having quit the Royal Marine training in a rather emotional escape he began as a tea-boy for a theatre company before showing both his talent for making bad decisions and his more high-handed, belligerent side.
“His attempt at his own production company failed after he featured royal events and had even been accused of invading his own nephew’s privacy.
“But then as Charles, Anne and Andrew created an unexpectedly low bar in terms of marriage survival rates, now suddenly it’s Edward looking like the son with the relationship staying power after all.”
Their strong relationship may have been helped by Prince Edward’s willingness to let Sophie take the lead, Judi claimed.
She explained Prince Edward is proud of Sophie for stepping into her role so well.
Judi added: “Edward’s non-verbal signals suggest he has happily moved into a more low-key role in public, while Sophie’s confidence signals show her as being the more socially active one in the team dynamic.
“Edward looks delighted to stand by his wife using glances of admiration and pride.
“He places his hands behind his back to suggest it’s her show, but his overall mirroring of her mood and posture shows they share like-minded thinking.”
Sophie’s attitude in the Royal Family may have also played an important part in their long-lasting marriage.
“Judging from her history and her body language I would suggest this is largely down to Sophie,” she continued.
“A successful PR with her own firm she integrated into the royal family in a very unfussy way and was a perfect complement for her husband’s trait of apparently taking himself a little too seriously.”