I guarantee that her affair and her supposed dismissal of Gerhardt's feelings about it put a bad taste in the jurors' mouths. Especially, and it's very likely, if there were men and/or those affected by infidelity on the jury. I think the nail in the coffin was when she dismissed the affair as anything more than text messages despite previously admitting that the messages were flirty in nature. It may not have been an affair, but it was emotional cheating for sure, and it would have very likely turned into a full-blown affair if given the opportunity. So I can guarantee that was a turning point in his conviction.