July 24, 2008 — -- The husband of murdered North Carolina jogger Nancy Cooper is finally speaking out about the state of his marriage, admitting he cheated and claiming that his wife did, too.
"Three years ago, I made a mistake while married to Nancy," Brad Cooper said in an affidavit filed Wednesday in Cary, N.C., and obtained by ABCNews.com.
"I had a single indiscretion and slept with another woman one time," said Cooper. "I deeply regretted [and still regret] that it happened."
While Cooper does not disclose the name of the woman in question, an affidavit filed by his wife's friends identifies her as Heather Heider-Metour, but does not delve deeper into how Cooper met her or the details of their relationship.
ABCNews.com was unable to contact Heider-Metour for comment.
Family and friends of Cooper's wife have been pointing fingers at her husband since the jogger disappeared just after 7 a.m. on July 12 and was found murdered two days later. They claim Cooper was abusive to his wife and even threatened suicide at one point -- claims Cooper adamantly denies in his affidavit.
Police have not named Cooper, 34, as a suspect or a person of interest in his wife's homicide.
In his affidavit, Cooper also alleges that his wife admitted to having an extramartial affair around the same time that he says he revealed his own indiscretions.
"Nancy admitted that she also had an extramarital relationship while married to me, four years ago," Cooper said in the document. "Nancy insisted that she did nothing wrong, that her relationship with the other man only happened once, it wasn't sexual and that no one even knew his name."
The Coopers were attending marriage counseling, according to the affidavit, but in April 2008 Cooper's wife prepared a separation agreement. At the time of her murder, Cooper had not yet signed the agreement.
In addition to addressing the state of his failing marriage, Cooper wrote extensively about his ability to care for his two daughters, Bella, 4, and Katie, 2, who have since been in the care of his wife's family after they were awarded emergency custody last week.
The 12-page affidavit goes into extensive detail about Cooper's love for his daughters, asserting that he feeds the girls "well-balanced meals" and even gave his wife a day off on the weekends -- known by the family as "mommy's day off" -- during which he'd care for kids.
Cooper recites the children's schedule meticulously, making a point of what an involved father he was to the girls.
The husband adds that while his children have been taken away from him since his wife's death, the separation papers drafted before the murder made clear that he was to share custody of the daughters.
"Nancy and her attorney agreed that I was a fit and proper parent to have the care, custody and control of the children," Cooper says in the affidavit.
The husband paints an ugly picture of his wife's family, who will petition for permanent custody of the girls in a hearing on Friday. He claims that his mother-in-law, Donna Rentz, has "fallen asleep at the wheel on at least two occasions" and has had "as many as seven major car accidents."
Alice Stubbs, the lawyer representing Nancy Cooper's family, declined to comment on Brad Cooper's affidavit when called by ABCNews.com.
In an affidavit filed Wednesday by Jessica Adam, one of Nancy Cooper's best friends who reported the jogger missing last week, Brad Cooper is described as "socially inept, selfish, moody and unpredictable."
In a 911 call released earlier this week, Adam was heard telling the operator, "Maybe her husband has done something."
Adam elaborates on her suspicion in the affidavit, saying that she was "immediately concerned that Brad had done something to her" when her friend failed to show up at her house for a prearranged get together.
Adam also alleges that Cooper had been recording his wife's telephone conversations, "repeatedly denied money to Nancy," and was "emotionally callous and verbally cruel" to his wife throughout their marriage.
But in his own affidavit, Cooper, who has stayed out of the spotlight throughout the investigation and was absent even from his wife's memorial service, addresses these allegations head-on, claiming that had it not been for his wife's unruly spending habits, a strict family budget would never have been needed.
"Our credit card debt was unmanageable, and Nancy could not control her shopping sprees," stated Cooper, who estimated that his credit card debt had reached approximately $45,000 due in part to his wife's adoration for an "$8,000 painting, designer clothing, Tiffany jewelry" and expensive bottles of wine.
While authorities have commended Cooper on his cooperation throughout the investigation, members of the community have not been shy in insinuating that Cooper may have had something to do with his wife's disappearance, allegations that Cooper himself addressed in his affidavit.
In the affidavit Cooper says that he attended a neighborhood barbeque with his wife the night before her disappearance, but returned home to put his kids to bed while his wife stayed at the party until midnight.
The next morning, said Cooper, he went out to buy milk for his daughters and, upon arriving home, was asked by his wife to go back to the store to pick up additional items.
"I started to get ready for the girls to get up and noticed we were out of laundry detergent and could not do laundry, so Nancy asked me to go back out to get some," said Cooper.
"The detergent I purchased did not include bleach," said Cooper, responding to rumors that he had been spotted on a local surveillance tape buying cleaning supplies the day of his wife's disappearance. "I did not buy bleach."
As for criticism that it was Nancy's friend and not him who reported his wife missing, Cooper said that he had been out canvassing the neighborhood and by the time he returned home to call the police -- once he was certain something was wrong -- Adam had already done so.
"I had been about to call the police myself to report her missing," said Cooper. "Once I knew the police had been called, there was no longer any point in calling them again."
Cooper claims that his absence during the search for his wife was due to requests by authorities who said that if he searched he would be "hindering the investigation."
Custody of the children for the upcoming year is set to be decided Friday by a judge in Cary, N.C.