As a military expert with ties around the world, Paula Broadwell kept a busy schedule packed with writing, teaching and helping wounded soldiers, leaving little time for the married mother to commit "indiscretions," a friend told ABC News.
"I have some serious questions about who is connecting these dots and how. ... Paula Broadwell is not the type ... she isn't," said David Bixler, an active duty double amputee who met Broadwell though a charity foundation in 2010.
As a biographer to Gen. David Petraeus, Broadwell enjoyed tremendous access to the general during the year they spent together in Afghanistan, finding out the idiosyncrasies that helped shape the man who was the public face of the war.
But what remained unseen was the extramarital affair that Petraeus told friends began after he left the army in August of 2011.
People close to Petraeus told ABC News they found Broadwell too "gushy" about the general, whom she viewed as a mentor, and commented to each other that they believed the 40-year-old was "in love with him."
It was clear in interviews Broadwell gave to promote her book, "All In: The Education of General David Petraeus," that she and the general shared a mutual trust.
The career of the four-star general, arguably the most respected military leader of his generation, came crashing down when the FBI stumbled upon the affair after probing an allegedly harassing email that had been sent from Broadwell to a woman in Florida.
In Broadwell's inbox, sources say investigators found emails that indicated she and Petraeus were having an extramarital affair.
By all accounts, Broadwell seemed to have it all.
The 40-year-old resides in Charlotte, N.C., with her husband, Dr. Scott Broadwell, who works as a radiologist, and their two young sons.
Growing up in Bismarck, N.D., Broadwell was the valedictorian and homecoming queen of her high school.
She went on to attend West Point, where she was ranked No. 1 in overall fitness in her class. She spent some time in the Black Ops and later earned post-graduate degrees from Harvard University and King's College in London.
On Monday, just days before before Petraeus would step down from his post with the CIA, a story by Broadwell was published on Newsweek's website titled "General David Petraeus's Rules for Living." No. 5 is notable in light of the news about his extramarital affair.
"We all will make mistakes," he said. "The key is to recognize them and admit them, to learn from them, and to take off the rear-view mirrors -- drive on and avoid making them again.""
Petraeus resigned on Friday, citing personal reasons and an extramarital affair.
"Yesterday afternoon, I went to the White House and asked the president to be allowed, for personal reasons, to resign from my position as D/CIA," he said in a statement. "After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair. Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours. This afternoon, the president graciously accepted my resignation."