Princess Diana was a devoted mom who made sure her sons Prince William and Prince Harry experienced life outside royal gates. Given her love for children, many have wondered why the People’s Princess didn’t have more kids. It turns out that her decision may have been in part because of Prince William.

A month before her untimely death in 1997, Princess Diana spoke with Ingrid Seward, a royal biographer. By that time, Princess Diana’s divorce from Prince Charles was official. She and Seward talked about whether she planned to get married again.

Seward says Princess Diana told her that Prince Harry was always asking his mother to have another child, the International Business Times reported. The young prince was reportedly fed up with being the youngest. But Princess Diana said she told Harry it was “difficult,” because she wasn’t married. But, here’s what the princess could have lost if she had remarried.

That said, Princess Diana was looking toward the future—and potentially more children. But Prince William and Prince Harry had very different views on the prospect of half-siblings.

“She said she’d love more children, and she didn’t see herself being single forever,” Seward revealed. “Harry wanted her to get married again, but William didn’t. He wanted Diana to be all there for him.”

Despite her eldest son’s wishes, Princess Diana expressed hope that she could find someone to marry who could “cope” with her, Seward said. What the princess didn’t say was that she had someone in mind. She had secretly been dating Dr. Hasnat Khan, a British-Pakistani surgeon—she even called him “The One,” just one of the things you never knew about their affair. She reportedly hoped to have two daughters with Khan, but the couple broke up shortly before her tragic accident.