Relationship expert Dr Pam Spurr sheds light on what we can expect for the soon-to-be-married couple.
All eyes are on Wills and Kate as they enter this new phase of their life, preparing for their marriage. But can we predict how happy they'll be? There are certain key elements to their personal histories and personalities that give us many clues.
Their different family backgrounds
Wills and Kate could hardly come from more different family backgrounds. Yes, of course Kate's come from a privileged, solid middle-class background but that's nothing like a royal background. Royal protocol and the prestige that goes with being a royal are almost impossible to imagine.
Unless William had chosen a fellow royal as his bride-to-be, no fiancée of his was ever really going to be clued-up as to what to expect despite being relatively privileged as Kate is.
The fantastic 'plus' about Kate's background is her parents have had a long and happy marriage that's given her great security. When you have a platform like that it gives you a basic confidence about relationships and a great role model to aspire to.
How they met the footing for an equal partnership
How Wills and Kate met was a fab beginning for what's become a long-term love story. They started out as equals, being young university students in a new city, having both moved to St Andrews in Scotland to study.
Although Wills would've had his security detail in tow, like Kate he would've been discovering everything about student life at the same time as she was. From making new pals, to forging a new social life, studying and facing exams, their lives mirrored each other's perfectly.
Meeting as equals gives a relationship superb balance right from the start. No one holds the upper-hand which would've been the case if, say, one of them had been a final year student who started dating a 'fresher'. Or as is so often the case when you meet someone at work, where one of you is higher up the ladder than the other, and that gives them the upper-hand.
They had the all-important 'P Factor'
Because of the circumstances in which they met, they immediately had a super-high level of what psychologists call 'propinquity' one of the main factors that predict attraction.
This means being in close contact on a regular basis in actual physical terms and for Kate and Wills this meant ending up as housemates. Plus they had it in social terms they wanted to hang out and do the same things. So forget the X Factor, their P Factor was high!
Her character, his character: why their mix should work
From observing them in news reports it's obvious they have a true bond of love. Their body language says it all they love and need each other. Although there are times when Kate's body language reveals nervousness and anxiety, Wills seems to pick-up on that and naturally reassures her with a little touch or look.
It's well-reported that Wills is a thoughtful man and combined with reports of Kate's loyal nature they have a really good mix of qualities to assure long-term success.
Both of them have a fun side that's at times revealed in late-night antics when they were younger but neither of them has shown themselves to be shallow, party-people. Again they seem to have a natural balance when it comes to wanting to go out like any other young couple but without any excessive behaviour that would get them in trouble.
Wills and Kate also both like the quieter life, too, and will relish their bolthole in Wales where they can get away from it all.
How their relationship is different to Charles and Diana's
You couldn't get a relationship that was more different to Wills and Kate's than the marriage of Charles and Diana. Sadly it was doomed right from the start when she was a very unsure and insecure bride, over a decade younger than her husband-to-be.
Diana went into the marriage believing in true love whereas Charles was much more aware of the ways of the world and that there were many obstacles in their way.
Although Diana's aristocratic pedigree was a good match for marriage to a royal, she was much more of a free spirit than royal life allowed. Because Charles and Diana had a weak bond in their marriage neither was prepared for the trouble ahead. And they didn't have a strong basis to create a team together and instead they pulled apart.
Why the future bodes well for this royal couple
Taking all of these factors into account Wills and Kate stand a fantastic chance of sticking together through thick and thin. They can look to her parents for how to do it when they face challenges. They can fall back on his humour and kindness and her loyalty and love when the going gets tough.
The balance and equality in their relationship will prove to be a great strength and their future looks happy and loving