The jury foreman mentioned verbal and emotional abuse as a reason for their difficulty resolving the death penalty issue.
It seems that was the issue of which the four jurors, who -- for whatever reasons -- couldn't vote for death, held onto as "mitigation".
I suspect that quite a few "death qualified" jurors lie ... even to themselves when at jury selection are being asked if they can render a punishment verdict of death. There's a large difference between saying "sure I can vote to sentence to death a
hypothetical evildoer" and saying "yeah, Jodi wasted Travis in an especially nasty way and for that I vote to have her executed".
This is where that 18 days of "testimony" by Jodi paid off: it "humanized" her, even with all of her lying & smirking & smart-ass evasions. She plays the wounded femininity part reasonably well, at least well enough to garner some sympathy when it got down to a decision if she's going to be sentenced to death.
I believe that ultimately it comes down to the age-old societal calculus: women's lives worth more than men's lives. Nowadays for a woman to be sentenced to death -- and get executed -- it takes multiple killings or killing another woman or something similarly heavy-duty. Killing a single man just doesn't seem to cut it anymore. It is kind of a reversal of the time when a woman who killed her husband was tried for
petit treason and the punishment was being burned at the stake.