Donald Trump has tried on and off for months to use Bill Clinton's infidelities against Hillary Clinton. Over the weekend, he appeared to suggest that the Democratic presidential nominee may have stepped out, too.

"Hillary Clinton's only loyalty is to her financial contributors and to herself," Trump told a crowd in Pennsylvania over the weekend. "I don't even think she's loyal to Bill, if you want to know the truth. And really, folks, really, why should she be? Right? Why should she be?"

Since Trump — a philanderer in his own right — is so curious about his opponent's sex life, he may like to know that the media once asked Hillary Clinton whether she was faithful to her husband. Clinton's answer then: "Yes."

The year was 2003, and the setting was a New York Barnes & Noble. Then a senator from New York, Clinton was promoting a new book, "Living History," in which she wrote about the Monica Lewinsky affair. Before a book signing attended by 1,200 people, Clinton held a news conference.

Here's how The Washington Post described the scene:

Clinton arrives at Barnes & Noble at 11 a.m. "Hello again," she says to a cluster of about 100 reporters and photographers. They are crammed between the Science Fiction and Fantasy shelves, a few feet from where Clinton will sign books. Her smile is tight and bright. She answers shouted questions, including one about whether she's always been faithful to Bill ("Yes"), and now that that's cleared up she can sell books.

The New York Post devoted a bit more time to the subject of Hillary Clinton's faithfulness:

Asked by reporters at a press conference before the book signing if she had ever strayed, the Democratic senator at first did a little dance.

"I think it's fair to say that in every marriage, there are moments of having to ask forgiveness for a multitude of things," she said. "I'm not going to answer specifically to all the many issues that come up in a marriage."

But when pressed if she had always been faithful, Clinton said with emphasis, "Yes."

The former first lady later said she shouldn't even have answered the question — and stressed that politicians' private lives were out of bounds.

The New York Sun took credit for posing the question:

Asked by the New York Sun if she had been faithful to Mr. Clinton, the senator said, flatly, "Yes." Then she paused. "I have to say, this is something that — I think the best answer to that was by Rosalynn Carter in her memoir when someone asked her, and she said, 'Look, if I hadn't, then I wouldn't tell you.' "

She told New York One, in an interview that aired yesterday evening, that a question about her faithfulness to Mr. Clinton "doesn't deserve an answer."

But the Clinton camp clarified later that she said she had never strayed from her marriage, the interviewer, Dominic Carter, said on-air after the piece ran.

In the current campaign, Clinton appears to have decided that Trump's latest innuendo does not deserve an answer, either. While 13 years have passed since that bookstore news conference, Clinton has addressed the topic in the past — and said she does not suffer from the wandering-eye disease that has afflicted her husband and her political rival.