After five years of dating, what caused Prince Harry and girlfriend Chelsy Davy to finally call it quits last week? Those close to the prince believe time and distance may have pulled the 24-year-old royal and the Zimbabwean-born beauty apart, People magazine reports in its upcoming issue, on sale Friday.

Chelsy, 23, is set to graduate from Leeds University this spring and is homesick for Africa, while Harry seems more committed than ever to army life.

When they split was announced, a royal source told People the pair felt their relationship “had run its course.”

Still, the news came as a shock to some of Harry’s friends. “I don’t see this as long-term,” a friend says of the couple, who broke up briefly in 2007.

Another pal, however, believes it’s for real. “It came right out of the blue,” he tells People. “But I don’t think if he was madly in love with her, he would have knocked it on the head. I think it is a case of, ‘Let’s call it a day; we had some fun.’”