“I made my debut at the Metropolitan Opera at the age of 27 and have sung at this magnificent theater for 51 consecutive, glorious years,” Mr. Domingo said in a statement. “While I strongly dispute recent allegations made about me, and I am concerned about a climate in which people are condemned without due process, upon reflection I believe that my appearance in this production of ‘Macbeth’ would distract from the hard work of my colleagues both onstage and behind the scenes. As a result, I have asked to withdraw and I thank the leadership of the Met for graciously granting my request.”

It sounded unlikely that he would ever be back to perform with the company.

“I am happy that, at the age of 78, I was able to sing the wonderful title role in the dress rehearsal of ‘Macbeth,’ which I consider my last performance on the Met stage,” he said. “I am grateful to God and the public for what they have allowed me to accomplish here at the Metropolitan Opera.”

The Met issued a statement that seemed to suggest that the company had asked him to go. “The Metropolitan Opera confirms that Plácido Domingo has agreed to withdraw from all future performances at the Met, effective immediately,” the statement said. “The Met and Mr. Domingo are in agreement that he needed to step down.”

The accusations against Mr. Domingo were first reported in August by The Associated Press, which wrote that he had pressured women into sexual relationships, and sometimes professionally punished those who had rebuffed him. (In addition to being a star singer, Mr. Domingo has held leadership positions at Washington National Opera and Los Angeles Opera, the companies where many of the accusers met Mr. Domingo.) The news agency’s initial report cited nine women, all but one of whom had been granted anonymity; a subsequent report cited 11 more women, one of whom was named.

The Domingo case roiled the Met, which is still recovering from the firing of its former music director, James Levine, last year amid accusations of sexual misconduct. In the #MeToo era, it also raised ongoing questions about how institutions deal with accusations of sexual harassment or abuse, even those that emerge outside their walls. And it posed a test for Mr. Gelb, who saw his initial decision — to go forward with Mr. Domingo’s performances as investigations into his conduct progressed elsewhere — grow increasingly untenable amid a growing outcry within his company.