Factbox: A look at other political sex scandals

Congressman Anthony Weiner speaks to the press in New York, June 6, 2011.

(Reuters) - Representative Anthony Weiner, embroiled in a sex scandal for sending lewd photos of himself to women over the Internet, has told House Democratic leader Nancy Pelosi he will resign from Congress, a party source said on Thursday.

The New York Democrat would become the third member of Congress this year to step down because of a sex scandal.

Under pressure from President Barack Obama and both major political parties, Weiner had previously insisted on staying in his job, announcing instead that would seek treatment and take a "short leave" of absence from the House.

Here's a look at what happened to some other lawmakers snared in sex scandals:

* Republican Representative Chris Lee of New York didn't put up much of a fight. He resigned in February -- just hours after it was disclosed that he sent a shirtless photo of himself over the Internet to a woman who is not his wife.

* Republican Senator John Ensign of Nevada tried to hang on. But he stepped down in May as an ethics committee was wrapping up an investigation into his affair with a former aide and an attempted cover-up. The matter ended Ensign's hopes of ever running for president.

* Republican Senator Larry Craig of Idaho rejected calls to resign. But he did not run for re-election in 2008 after he was arrested on charges of soliciting sex in an airport men's room.

* Republican Representative Mark Foley of Florida resigned in 2006 after it was disclosed that he had sent sexually suggestive e-mails to male pages.

* Republican Senator David Vitter of Louisiana asked for forgiveness and got it. He won re-election in 2010 -- despite having been identified as a client of a prostitution service.

* Democratic Representative Eric Massa of New York insisted he did nothing wrong. But he resigned last year to avoid an ethics probe into alleged sexual misconduct toward a male staffer.

* Republican Representative Mark Souder of Indiana resigned in 2010 after admitting that he had an affair with a female staffer. Souder left with a push from party leadership, which didn't want him to complicate their efforts to win back the House from Democrats in last year's election.

* Representative Barney Frank, who is gay, was reprimanded by the House in 1990 after an ethics probe into his hiring of a male prostitute as a personal aide. The Massachusetts Democrat not only survived calls to resign, but became one of the House's most powerful members, one known for his sharp mind and biting wit.

(Reporting by Thomas Ferraro; Editing by Doina Chiacu and Eric Beech)