The LA Times reports:
CIA Director David H. Petraeus was shocked to learn last summer that his mistress was suspected of sending threatening emails warning another woman to stay away from him, former staff members and friends told the Associated Press on Monday.
Petraeus told the associates his relationship with the second woman, Tampa socialite Jill Kelley, was platonic, but his biographer-turned-lover, Paula Broadwell, apparently saw her as a romantic rival. Petraeus, a retired four-star Army general, also denied to these associates that he had given Broadwell any of the sensitive military information alleged to have been found on her computer.
The associates spoke on the condition of anonymity because they weren't authorized to publicly discuss the matters, which could be part of an FBI investigation.