Former CIA Director David Petraeus is admitting to close friends that he "screwed up royally," calling his affair with his biographer a big mistake.

In early November, Gen. Petraeus stepped down after his indiscretion with his biographer Paula Broadwell came to light.

Petraeus confessed that he has created enormous difficulty for his wife, Holly.

"I paid the price appropriately and I sought to do the right thing at the end of the day," he wrote in a letter to friends last week.

Nevertheless, he said his wife is standing by him.

"Team Petraeus will survive though it has obviously created enormous difficulty for us. Holly is however once again demonstrating how incredibly fortunate I was to marry her," he wrote.