Wes Goodman, a state legislator for Ohio, has already been forced to resign after a witness to the reported extramarital affair told the Ohio House Chief of Staff.
But now Mr Goodman is facing a host of complaints after alleged victims shared screengrabs of conversations with right-leaning news website the Independent Journal Review.
Mr Goodman, who routinely promotes “family values”, is married to a woman who is an assistant director of an annual abortion rally known as March for Life.
According to the IJR, Mr Goodman would regularly contact men, usually aged between 18 and 24 and in the Republican movement, on Facebook Messenger.
The conversations frequently turned sexually explicit, with Mr Goodman sending suggestive messages and photos of his genitalia on Snapchat, reports the website.
One alleged victim, who wished to remain anonymous, told the IJR he received a friend request from Mr Goodman, who started discussing “various political things” before a two weeks later asking for the man’s Snapchat details.
“He constantly sent me Snaps and was always commenting on my stories,” the victim said. “He also asked how much 'p***y' I was getting and wondering what I was doing on Friday and Saturday nights.”
He added: “Then, he sent me videos of him masturbating as well as d**k pics. He also sent another Snapchat asking how big my penis was.”
Dozens of men shared similar experiences of their online encounters with Mr Goodman, according to the IRJ.
The politician was also accused of groping an 18-year-old student in 2015 after a fundraiser, according to the Washington Post.
Mr Goodman, whose Twitter biography describes him as “Christian. American. Conservative. Republican. Husband to @Beth1027”, has regularly claimed "natural marriage" occurs between a man and a woman.
"Healthy, vibrant, thriving, values-driven families are the source of Ohio's proud history and the key to Ohio's future greatness,” his campaign website said.
“The ideals of a loving father and mother, a committed natural marriage, and a caring community are well worth pursuing and protecting."
The website has now been taken offline.
Mr Goodman, who has been described as a “conscience of the conservative movement”, announced in a statement on Thursday that he was stepping down.
“We all bring our own struggles and our own trials into public life," he said.
"That has been true for me, and I sincerely regret that my actions and choices have kept me from serving my constituents and our state in a way that reflects the best ideals of public service.
"For those whom I have let own, I’m sorry. As I move onto the next chapter of my life, I sincerely ask for privacy for myself, my family, and my friends.”