Kate Middleton is set to resume her royal duties this week after her reclusive four-month maternity leave. But despite efforts to save her failing marriage to Prince William, with Queen Elizabeth II's intervention, a new report claims the Duchess of Cambridge's marital life is still in crisis. The reason? She feels alarmed with the Duke's ex, Isabella Calthorpe.

It has been reported that Isabella Calthorpe, who is Prince Harry's ex Cressida Bonas' half-sister, is Prince William's first choice for his wife. That's why, Kate Middleton appeared to be quite paranoid over her. According to Celeb Dirty Laundry, the Duchess felt threatened that Calthorpe might tempt the 33-year-old Duke of Cambridge into a cheating scandal.

Since Prince Harry is somewhat connected with Calthorpe through her half-sister Cressida Bonas, who is his ex, Kate Middleton is allegedly pushing her brother-n-law to rekindle romance with Chelsy Davy. But royal watchers are definitely wondering how the cheating scandal will materialize since both Prince William and Isabella Calthorpe have already their own families. Do you think the 33-year-old Duchess' fears are unwarranted?

Related: Kate Middleton, Prince William Divorce POSTPONED? Shocking Retirement Of Queen Elizabeth II Infuriates Prince Charles [RUMORS]

Meanwhile, another royalty is currently making headlines and it's none other than Prince Harry, one of U.K.'s most eligible bachelors. The 30-year-old royal blood is allegedly rekindling his romance with his former squeeze, Chelsy Davy. Daily Express revealed the ex-lovers met in South Africa recently and "openly discussed" the possibility of giving their relationship a second chance, four years after breaking up.

"There is still very much something between them. Harry has never fallen out of love with Chelsy," a friend close to the exes said.

Prince Harry and Chelsy Davy, 29, met in Cape Town in 2004 during the prince's gap year. Their first round in the relationship was on-and-off but lasted for seven years. Eventually, they broke up in 2011, just after Kate Middleton and Prince William's royal wedding, People noted.

Related: Prince Harry Finally Dating? Princess Charlotte's 'Bad Uncle' Feels Guilty On Ditching Niece's Christening

The royal lives of Kate Middleton, Prince William and Prince Harry are indeed getting more and more interesting. Do you think William will cheat on Kate? Or is Chelsy Davy the woman Harry is waiting for to settle down?

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