The 35-year-old actress - who announced she had separated from the director in March 2010 after almost seven years of marriage - feels as though she is currently at a time in her life when she needs to be single.
And the Oscar winner now just wants to concentrate on her two children - 10-year-old Mia, her daughter with ex-husband Jim Threapleton, and seven-year-old Joe, her son with Sam.
Kate - who embarked on a brief relationship with Burberry model Louis Dowler a few months after her marriage ended - said in an interview with Vogue magazine: "Experiencing those moments of being alone ... is a very, very weird flooring and exposing position to be in when you`re just not used to it. And it`s not just being in a relationship. It`s also the fact that I grew up in a family full of people.
"But I`ve never been lonely. And with my kids Mia and Joe that remains the case.
"But to be in this place now where I can say I really like this space. I really need to not have anyone around. It`s a surprise to discover that I like being on my own.