The much-anticipated ruling on whether Fani T. Willis should be disqualified from prosecuting former President Donald J. Trump and 14 of his allies in Georgia came on Friday, requiring her to make an unusual decision.

Ms. Willis, the district attorney in Fulton County, Ga., can keep control of the state election interference case that has been more than three years in the making, but only if Nathan J. Wade, a former boyfriend, withdraws from the case, which she hired him to manage.

For much of this year, headlines and hearings delving into the romantic relationship between the two prosecutors have overshadowed the case itself, in which the defendants are charged with conspiring to thwart the will of Georgia voters after Mr. Trump lost the 2020 presidential election.

Defense lawyers brought to light the relationship between the prosecutors, saying it had created an untenable conflict of interest. But Judge Scott McAfee of Fulton Superior Court rejected that argument on Friday, while sharply criticizing Ms. Willis for a “tremendous lapse in judgment.”

Here are takeaways from the ruling:

The judge found an appearance problem, but not an actual conflict.

Judge McAfee said there was not enough proof to find that Ms. Willis’s “personal relationship and recurring travels with her lead prosecutor” created “an actual conflict of interest.”

He added that “Georgia law does not permit the finding of an actual conflict for simply making bad choices — even repeatedly — and it is the trial court’s duty to confine itself to the relevant issues and applicable law properly brought before it.”