They Were On A Break! Inside Kate Middleton & Prince William's Summer Split

Boys will be boys — and that even goes for princes! The Duke and Duchess of Cambridge may look like the perfect couple, but the two hit a rough patch in the beginning of their relationship.

After dating for three years while at university together, Kate Middleton and Prince William broke up one summer when the Duke went on an all-boys sailing trip with an all-female crew. According to Robert Lacey's new book, Battle of Brothers, the royal pair split in 2004 prior to their second split in 2007.

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"In the summer of 2004, with just a year to go until William's graduation, he rather welcomed the mischievous suggestion of his friend from childhood, Guy Pelly, that he might leave Kate at home and join his friend on a 'boys only' sailing trip to Greece," Lacey explained. The father-of-three's good pal then suggested "that the yacht might be staffed and operated by an all-female crew. Kate was not impressed, and made sure William knew it."

Distraught Kate — who lived with William at that time — went back to her family in Berkshire while her beau enjoyed his all-guy getaway. The duo, however, "committed to go back to Balgove House for their fourth and final year." The pair kept to their word, and at the end of September 2004, they found themselves reunited "and actually stronger, on reflection, for the time spent apart."

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Another biography, The Duchess of Cambridge: How Kate Middleton Became A Future Queen, revealed the mother-of-three was devastated during their brief time apart. One of Kate's pals explained that "she got quite drunk on white wine and really let her guard down. She was debating whether or not she should text or call him," the friend dished. "She said how sad she was and how much she was missing William but she never mentioned it after that."

The power couple met in 2001 when they both attended the University of St. Andrews. The young students were in the same hall, with rooms quite close to one another. The royal couple attended the same party one night during their first term of school. The Prince was getting heavily hit on by a pushy girl when the angelic Kate came to save the day. She appeared from behind and wrapped her arms around the charming William. "Oh sorry," he said to the pushy girl, "but I've got a girlfriend," and he and Kate went off giggling together. "Thanks so much," he mouthed to her.

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The brunette beauty then made sure to catch William's eye by strutting down the runway in a sheer dress — which showed off her underwear and bra — at a university fashion show that same year, which raised money for a 9/11 fundraiser.

From there, their romance quickly heated up. The pair moved into a flat together their second year of school with other friends. The following year, the couple, both 38, moved into a "romantic" home, Balgrove House, together. Their quant home quickly became known as the party hotspot with Kate dishing up meals for their dinner parties.

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After their on-again-off-again courtship, the Duke proposed to Kate in Kenya in 2010. The royals' tied the knot the following year and welcomed Prince George in 2012, Princess Charlotte in 2015, and Prince Louis in 2018.