NO. She's not. 

Kate Middleton is currently enjoying  a family break with her beloved husband, Prince William, and three children, Prince George,  Princess Charlotte and Prince Louis.

The speculations about divorce started after reports in the British media said Prince William hired Mishcon de Reya, the law firm that represented Princess Diana during her divorce from Charles, to act on his and his family's behalf. 

This move is seen as a break from tradition, as William previously used his father King Charles's lawyers.

The firm specializes in areas like divorce and family law, which may be beneficial for William's personal and family needs. 

After the reports regarding the law firm were published, some people started speculating that this change might be related to William's marriage to Kate Middleton, but there's no concrete evidence to corroborate this claim. 

The supporters of the Prince and Princess of Wales see his decision as a sign of William's growing independence.

Prince William continues to support his wife as she recovers from cancer  which was diagnosed last year.

The Princess of Wales completed her chemotherapy in August last year and is making a gradual return to royal duties.