Prince William and Kate Middleton don’t engage in PDA as much as Prince Harry and Meghan Markle.

On the online forum site Quora, some royal fans shared their thoughts on why they think the Cambridges act differently from the Sussexes especially when they are out in public.

Christina Lundy, a former sous chef, said that Prince William and Middleton are adults and they also act like grown-ups. Since the Duke and Duchess of Cambridge have important roles in the British monarchy, it is evident that they are taking their roles of representing the royal family very seriously.

“Because they are not trying to make a spectacle of their relationship. Because they are not trying to show a unity that is not there. Because they don’t need to prove anything to anyone. Because they are sincere. Because they know how to be classy. Because they understand the love is between them and nobody else’s business,” Lundy said.

Mary Maclaughlin, who works at Animal Rescue, said that Prince William and Middleton’s lack of PDA doesn’t mean that they don’t love each other as much as Prince Harry and Markle love each other. Rather, it is due to their elevated positions within the royal family.

“While many royal fans love the way that Meghan and Prince Harry seem like a ‘real’ couple, they have also received some criticism for their supposedly ‘non-royal’ ways. Still, they aren’t obligated to be as formal as Prince William and Catherine, simply because they don’t have as much responsibility and will likely never have to rule,” she said.

Three years ago, royal etiquette expert Myka Meier told People that there’s really no royal protocol when it comes to public displays of affection. But she said that Prince William and Middleton likely show very little PDA to remain professional especially when they are representing Queen Elizabeth II.

Body language expert Robert Kermode also pointed out that Her Majesty and Prince Philip rarely engage in PDA as well. And this seems to have set an unwritten precedent for some members of the royal family.

Is This Real Reason Prince William, Kate Middleton Avoid PDA Unlike Harry, Meghan? Pictured [L-R]: The Duke of Cambridge, Duke of Sussex, Duchess of Sussex and Duchess of Cambridge arrive at Westminster Abbey to attend a service to mark the centenary of the Armistice on Nov. 11, 2018 in central London. photo: Paul Grover/AFP/Getty images