Craig Schelske did not identify the other man in court documents filed Friday in Williamson County Chancery Court. Evans' publicist Lori Genes declined to comment.
In his answer tofiled last week, Schelske denies Evans' allegations that he committed adultery, was verbally and emotionally abusive, drank excessively and frequently watched pornography in their home.
Schelske, 43, also says his wife's interest in her "marital roles and responsibilities" declined and she "neglected" their three children after she began appearing on ABC's "Dancing with the Stars." Evans, 35, quit that show in a surprise announcement last week.
Schelske, who ran for Congress as a Republican from Oregon's 5th District in 2002, denies her claims that he posed for nude photographs of himself, except a few taken by his wife on their 10th wedding anniversary, as well as the existence of any sexual photographs of himself with other women, or that he had an affair with their former nanny. The nanny also has denied the allegation.
"No other photographs exist and any allegations of such are outrageous, defamatory, malicious and legally actionable," the suit states.
In a "Dancing with the Stars" interview aired Tuesday, Evans admitted that there were problems in their marriage when she signed on to do the twice-weekly reality show. But she thought she could mend the relationship and do the show at the same time.
"I'm completely against divorce. My intention was to continue to try everything within my power."
Things began to worsen after Evans received a report last Tuesday about pornographic photos found on her husband's computer.
Somehow, she was able to make it through the show that night.
"The good thing is that I'm so used to performing," said Evans "and as you know, as entertainers we have that ability to just sort of flip the switch. Turn it on, do the dance and, you know, make it through the day. That's what I was hoping was going to happen throughout the entire life of the show."
But working on the show and going through the process of divorce proved too difficult for Evans. After the results show on Wednesday night, Evans acknowledged that "something happened" at her home.
"It was something personal and traumatic and hard for my children," she said. "Things went drastically downhill, 100 miles an hour."
She said that she realized at that moment that she needed to be at home with her children, not on the dance floor.
"I needed to be right there," she said, "to look at my son at all times to see the expression on his face and, you know, see if he's crying. I put him on the phone with our pastor immediately. I knew that nothing in my career, no television show, nothing was more important than that."
The country singer's departure had an effect on the show's other stars. "Sara was cool and I miss her a lot," said fellow contestant Mario Lopez. "We dedicate this night to Sara and wish her nothing but the best."
One person who will have a chance to work with Evans again is her professional dance partner on the show, Tony Dovoloni. Evans announced that she's tapped him to choreograph her tour next year.
Evans closed by thanking her fans for being supportive.
"I have felt so much love and support from the fans, even before all this happened," she said. "It's so humbling and I'll never forget it. I will never forget every second of this experience. I just want to, you know, thank everybody from the bottom of my heart and I will come back for the finale if I'm invited."