Xerez president quits following threats
"I have resigned for personal reasons," De Osma told a news conference on Thursday, "I have received threats, as have my wife and children.
"If people want to have a team in La Liga it depends on everyone, not just the players. Cutting down the criticisms would help."
Xerez lost 2-0 at home to champions Barcelona on Wednesday, and have managed only one win in their first top-flight campaign.