The 46-year-old actress, who played witch Bellatrix Lestrange in the Harry Potter films, has gone to such lengths to keep her love for Burton alive that they live in interconnected houses decorated to each one's taste.
Now, Carter is planning to cut down on acting assignments to focus on family, The Telegraph reported.
"Juggling motherhood with acting is hard and I'm dropping all the balls at the same time. You always feel like you're doing everything badly," she said at the London Critics' Circle Film Awards, at the May Fair Hotel.
The couple live with their children, Billy, 10, and Nell, six, as well as a nanny, in three converted former artist's studios in north London.
"Tim's taking time out now, and I think I'll do the same. We're trying to be parents, which is harder than anything else," said Carter.