The Rev. Ted Haggard resigned as president of the 30 million-member association Thursday after being accused of paying the man for monthly trysts over the past three years.
Haggard, a married father of five, denied the allegations, but also stepped aside as head of his 14,000-member New Life Church pending an investigation.
The acting senior pastor at New Life, Ross Parsley, told CBS affiliate KKTV-TV of Colorado Springs that Haggard admitted that some of the accusations were true.
"I just know that there has been some admission of indiscretion, not admission to all of the material that has been discussed, but there is an admission of some guilt," Parsley told the station. Parsley added that the church remains "100 percent for him."
In an e-mail addressed to church members about Haggard, Parsley wrote, "It is important for you to know that he confessed to the overseers that some of the accusations against him are true. He has willingly and humbly submitted to the authority of the board of overseers, and will remain on administrative leave during the course of the investigation," CBS affiliate KCNC-TV in Denver reports.
In a statement, Haggard said, "so that the overseer process can be allowed to proceed with integrity. I hope to be able to discuss this matter in more detail at a later date. In the interim, I will seek both spiritual advice and guidance."
Carolyn Haggard, spokeswoman for the New Life Church and the pastor's niece, said a four-member church panel would investigate the allegations. The board has the authority to discipline Haggard, including removing him from ministry work.
The allegations come as voters in Colorado and seven other states get ready to decide Tuesday on amendments banning gay marriage. Besides the proposed ban on the Colorado ballot, a separate measure would establish the legality of domestic partnerships providing same-sex couples with many of the rights of married couples.
Church members were stunned by the allegations.
"It's political, right before the elections," said Brian Boals, a New Life member for 17 years.
Church member E.J. Cox, 25, called the claims "ridiculous."
"People are always saying stuff about Pastor Ted," she said. "You just sort of blow it off. He's just like anyone else in the public eye."
The accusations were made by Mike Jones, 49, of Denver, who said he decided to go public because of the political fight over the amendments.
"I just want people to step back and take a look and say, 'Look, we're all sinners, we all have faults, but if two people want to get married, just let them, and let them have a happy life,"' Jones said, adding that he was not working for any political group.
Jones, who said he is gay, said he was also upset when he discovered Haggard and the New Life Church had publicly opposed same-sex marriage.
"It made me angry that here's someone preaching about gay marriage and going behind the scenes having gay sex," he said.
Jones claimed Haggard paid him to have sex nearly every month over three years. He said he advertised himself as an escort on the Internet and was contacted by a man who called himself Art, who snorted methamphetamine before their sexual encounters to heighten his experience.
Jones said he later saw the man on television identified as Haggard and that the two last had sex in August.
He said he has voice mail messages from Haggard, as well as an envelope he said Haggard used to mail him cash. He declined to make the voice mails available to the AP, but KUSA-TV reported what it said were excerpts late Thursday that referred to methamphetamine.
"Hi Mike, this is Art," one call began, according to the station. "Hey, I was just calling to see if we could get any more. Either $100 or $200 supply."
A second message, left a few hours later, began: "Hi Mike, this is Art, I am here in Denver and sorry that I missed you. But as I said, if you want to go ahead and get the stuff, then that would be great. And I'll get it sometime next week or the week after or whenever."
Haggard, 50, was appointed president of the evangelicals association in March 2003. He has participated in conservative Christian leaders' conference calls with White House staffers, such as Karl Rove, and lobbied members of Congress last year on U.S. Supreme Court appointees after Sandra Day O'Connor announced her retirement.
After Massachusetts legalized gay marriage in 2004, Haggard and others began organizing state-by-state opposition. Last year, Haggard and officials from the nearby Christian ministry Focus on the Family announced plans to push Colorado's gay marriage ban for the 2006 ballot.
At the time, Haggard said that he believed marriage is a union between a man and woman rooted in centuries of tradition, and that research shows it is the best family unit for children.