The course of love hardly ever runs smoothly - just ask the Duke and Duchess of Cambridge.
They might have now been married for almost 11 years and have a happy family life with their three children - Prince George, Princess Charlotte and Prince Louis - but in the early years of their romance after they left St Andrews University where they met, they endured a brief split.
The couple went their separate ways in 2007, and it was feared that they had called time on their relationship for good.
But thankfully, the split was short-lived and they reunited - in part thanks to jockey Sam Waley-Cohen, who won the Grand National on Saturday.
So how did Prince William and Kate end up splitting and how did Sam help bring them back together? Here we take a look...
William's doubts
It's well-known that William and Kate officially became an item during their time at St Andrews University in Scotland.
They were friends at first, but romance quickly blossomed and by the time they graduated in 2005, they seemed to be a solid partnership.
After graduation, William went into the military, while Kate took a job in London as an accessories buyer at Jigsaw.
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But by 2006, the cracks had started to appear and one royal expert said that William confided in the Queen and Prince Charles over his doubts about a future with Kate.
It is thought that William got cold feet as speculation grew about an imminent engagement.
And expert and author Katie Nicholl said that during Christmas in 2006, William had become so anxious he had a meeting about it with his father and grandmother.
She explained: “William had been having second thoughts and sat down with his father and his grandmother to have a frank discussion about his future with Kate. Both advised him not to hurry into anything.”
However, that festive period also reportedly left Kate fearing for the relationship as a book claims William cancelled plans to spend New Year with her and the Middleton family.
In her book released in 2011, The Making of a Royal Romance, royal author Katie claims William had promised Kate he would join her family but decided to stay with his family instead - informing her on the phone on Boxing Day.
'Phone call' that ended it
By 2007, when Kate was 25 and William 24, their relationship was said to be on the rocks.
And it was reported at the time that they called time on their romance during a phone call that Kate took while at work.
One of her former colleagues told the Mirror in April 2007 that they saw Kate take the call in the office car park in London.
They said: "It was clear it was William - and definitely a tiff."
The incident was also covered in royal author Robert Lacey's book Battle of Brothers, which also claims that Kate and William split during that call.
The book claims that Kate excused herself from a meeting to take a call from William - then a "hard-drinking" Army officer often spotted at nightclubs - and shut herself in a room for more than an hour while the pair discussed their future.
Kate's single life and William's regrets
Kate may have been heartbroken by the split, but in public, she put on a brave face.
She enjoyed nights out at London hotspots, was pictured with William’s friends and gave a glimpse of a cheeky self-help book in her handbag, entitled Love Is Not Enough: A Smart Woman’s Guide To Keeping (And Making) Money.
She even signed up for an all-female dragon boat race team that aimed to row across the English Channel to raise funds for children’s hospices.
However, friends of the couple said it wasn’t much more than two months after the split that William began to miss her.
Royal historian Robert Lacey described how the prince “got the message quicker than he or anyone else expected”.
Among those helping get the couple back together was Kate's friend and now Grand National-winning jockey Sam Waley-Cohen.
Despite awkwardness surrounding the breakup, the jockey decided to invite both of them to his 'Freakin Naughty-themed party' at his family's Oxfordshire mansion.
According to MailOnline, Wills wore hot pants and a policeman helmet and Kate was dressed as a naughty nurse in fishnets.
They were reportedly seen in deep conversation during the evening, and within just a few weeks they were back together.
However Sam always plays down his role, saying in 2011: "There’s an idea that I was like Cupid with a bow and arrow. People love the idea that somebody put them back together, but they put themselves together far more."
Kate and Sam became pals under tragic circumstances, as the Duchess was originally friends with the jockey's younger brother Thomas.
Thomas died in 2004, just days after his 20th birthday. He was diagnosed with the bone cancer Ewing’s sarcoma in 1995.
After Thomas's death, Kate organised a charity roller disco in London to raise money for a paediatric surgery ward named after him.
She's pictured at the event wearing yellow hot pants and a green sequin top, while Sam wore a bright pink blazer with an orange top.
Romance back on
After the reunion, William and Kate were seen kissing at an Army party at barracks in Bovington, Dorset.
And in July 2007 Kate and her brother James were seen at the Concert for Diana, held at Wembley to mark 10 years since William’s mother’s death. They were a few rows behind William, Prince Harry and his then-girlfriend Chelsea Davy.
Kate then attended the wedding of William’s cousin Peter Phillips to Autumn Kelly, taking William’s place, while he attended a friend’s wedding in Africa.
It wasn’t long before their romance was confirmed to be back on, and Kate moved into William’s Clarence House flat, where he would return from military duties on Friday nights for cosy weekends together.
Engagement at last...
Three years after the brief split, it was revealed that William and Kate were engaged, with the bride-to-be given the late Princess Diana's engagement ring.
And in an interview to mark their engagement, they shared their feelings about the split.
Kate admitted: “At the time, I wasn’t very happy about it, but it made me a stronger person.
“You find out things about yourself that maybe you hadn’t realised.
“I think you can get quite consumed by a relationship when you’re younger. I really valued that time for me as well, although I didn’t think it at the time.”
While William said: “We were both very young… we were both finding ourselves and being different characters. It was very much trying to find our own way and we were growing up, so it was just a bit of space and it worked out for the better.”
