Filner said last week that he believes he will be vindicated by "a full presentation of the facts." But he has also acknowledged, "I need help," and added, "I'm clearly doing something wrong."
"I am embarrassed to admit that I have failed to fully respect the women who work for me and with me, and that at times I have intimidated them," Filner said in a statement earlier this month. "It's a good thing that behavior that would have been tolerated in the past is being called out in this generation for what it is: inappropriate and wrong."
Filner, 70, served five terms in Congress before being elected mayor in 2012. He has said he will not resign.
Jackson said she decided to resign after Filner's deputy chief of staff resigned in June. Filner "refused to listen to someone he had known for 35 years, and who told him explicitly, during a senior staff meeting, that his behavior with women was terrible and possibly illegal."
Filner "laughed it off," she said. She said Filner challenged her to provide one example of improper behavior; when she brought up his comments about wearing underwear, "he had no comeback," she said.