(CNN) Rob Porter, a top White House aide with regular access to President Donald Trump abruptly resigned on Wednesday amid abuse allegations from two ex-wives, who each detailed to CNN what they said were years of consistent abuse from Porter, including incidents of physical violence.

Colbie Holderness, Porter's first wife, and Jennifer Willoughby, Porter's second wife, both said their ex-husband's consistent abuse was the reason for their respective divorces.

Porter denied the allegations in a statement issued in the wake of his resignation.

The allegations were first reported earlier this week by the Daily Mail.

"These outrageous allegations are simply false," he said in his statement. "I have been transparent and truthful about these vile claims, but I will not further engage publicly with a coordinated smear campaign."

White House chief of staff John Kelly called Porter "a man of true integrity and honor and I can't say enough good things about him."

"He is a friend, a confidante and a trusted professional. I am proud to serve alongside him," Kelly said in a statement.

Colbie Holderness

In a lengthy interview, Holderness, who married Porter in 2003, told CNN on Wednesday that the physical abuse began almost immediately after their wedding. The couple went to the Canary Islands for their honeymoon in the summer of 2003, when Holderness said Porter kicked her thigh during a fight.

"I didn't quite know how to take it," Holderness said. "I had just tied the knot with him."

She said that Porter's repeated physically abusive behavior also included throwing her on the bed and forcefully pushing one of his limbs into her body in anger and choking her.

"The thing he would do most frequently is he would throw me down on a bed and he would just put his body weight on me and he'd be yelling at me but as he was yelling he'd me grinding an elbow or knee into my body to emphasize his anger," she said. The choking, she said, "was just very scary and dehumanizing," and she said she didn't realize the severity of the situation until she spoke with a counselor.

In the summer of 2005, the couple was in Florence, Italy, when Holderness said he punched her in the face -- the only time, Holderness says, when she remembers her ex-husband leaving a physical mark on her body.

"I think it shocked him and it shocked me. It never happened again, it was a one-time thing," she said.

CNN obtained this image of Colbie Holderness from 2005, who is the first ex-wife of White House staff secretary Rob Porter who resigned on Wednesday, February 7.

Holderness shared photos Porter took of her with CNN. Porter said in a statement that he had taken the photographs.

"I took the photos given to the media nearly 15 years ago and the reality behind them is nowhere close to what is being described," he said.

Holderness said though Porter did take them, she stands by her account.

"He's wrong in that the circumstances are exactly what I described. In contrition I made them take the photos. In his contrition, I had him take photos of what he did," she told CNN.

Her brother, Trevor Paulson, and a close girlfriend who declined to be named, both told CNN on Wednesday that Holderness had confided in them over the years about Porter's abuse.

Jennifer Willoughby

Willoughby, who married Porter in 2009, told CNN that she also endured deeply disturbing emotional abuse from her ex-husband. During their honeymoon in Myrtle Beach, the bursts of anger that she had already become familiar with were "more intense," she said.

"He started calling me names, calling me a 'f---ing bitch,' how I behaved was 'f---ing ridiculous' and most of that was instigated around my not having sex with him often enough on our honeymoon," Willoughby said.

Similar to Holderness and Porter, Willoughby said she and Porter also sought therapy and eventually separated.

Around the spring of 2010, Willoughby said Porter came looking for her at their previously shared home and it appeared that he had punched a glass pane on the front door.

"The window on the door was broken and his hand was bleeding and he was requesting to be able to come in and seek medical attention. At that point, I was scared, and he also wasn't supposed to be there to begin with," she said.

The police eventually came and recommended that she take out a temporary protective order. CNN reviewed a copy of the order dated June 2010.

The only incident, Willoughby said, in which Porter physically abused her was in December of 2010.

"We were in a fight and I disengaged from the fight after screaming at each other. I took a shower and Rob followed me fairly shortly after and grabbed me from the shower by my shoulders up close to my neck and pulled me out to continue to yell at me," she said. "He immediately saw the look of shock and terror on my face and released me and apologized and attempted to make things right."

She said the two divorced in 2013.

A third woman

Both Holderness and Willoughby were contacted by a woman claiming to be Porter's girlfriend in 2016. In Facebook and text messages reviewed by CNN, the woman, described "repeated abuse" from Porter and sought help from the ex-wives on how to leave him.

"I work in politics, and despite Rob's repeated abuse, some of which I think many know about, he continues to rise and I'm afraid to go against him," the woman wrote to Holderness in December 2016. "I'm sorry to bother you. I wanted to reach out and hear your story if you are willing to share -- as well as how you broke out of it with him and mostly, how you recovered."

"Rob was abusive, degrading, a liar and a cheater and during the course of my relationship with him, I found out that he was to others, too," the woman wrote to Willoughby in February 2016. "I am just searching for someone who might be able to relate to the hell I have gone through."

The woman currently works in the federal government. CNN has repeatedly attempted to reach her and is not naming her.

White House role

Both Holderness and Willoughby said they were contacted by the FBI last year and interviewed regarding Porter's security clearance. Both women told CNN that they were honest with the FBI about their respective troubled marriages.

A source familiar with the matter said Porter ran into trouble obtaining a security clearance for working at the White House when one of his ex-wives raised the issue of domestic violence with investigators.

Porter has been dating White House communications director Hope Hicks, one of the most influential figures in the West Wing, several people familiar with their relationship say.

A former chief of staff to Sen. Orrin Hatch, Porter joined the White House at the beginning of Trump's administration, though he wasn't well-known to the President like other top West Wing staffers.

As staff secretary, Porter's responsibility was mainly in the flow of paper that crossed Trump's desk, including the wave of executive orders and actions that Trump inked during the first months of his tenure. A lawyer, Porter also participated in the process of legal vetting the myriad documents that require the President's signature.

Porter's role was under-the-radar, and Trump himself remained largely unfamiliar with him for weeks before his role was explained. The President was impressed by Porter's educational credentials — including degrees from Harvard and Oxford — a person familiar with the matter said.

When John Kelly replaced Reince Priebus as White House chief of staff, Porter's role expanded. Kelly imposed a strict system of information flow to the President, elevating the importance of Porter's task in managing the documents, news clipping, and briefing books that entered the Oval Office.

He was also seen as a neutral arbiter between warring West Wing factions, helping bridge gaps between those who worked on Trump's campaign and the faction of aides who came from other Republican circles. Kelly in particular viewed Porter as a right-hand man who would impose his system of order even in his absence.

Porter began traveling more frequently in Trump's entourage, including during last month's trip to the World Economic Forum in Davos. Kelly himself remained behind in Washington, as did the top policy adviser Stephen Miller.

A person familiar with West Wing dynamics said Porter has expressed interest in an elevated policy role over the past weeks, beyond the position he currently holds. He's been approached by private sector firms over the past several months with offers to leave the administration, and has considered them, but told colleagues earlier this year that he wasn't planning on leaving the White House, the person said.

White House staff secretaries play an important role in the West Wing, though the position has varied in stature. Under President Barack Obama, the role was downgraded to a "deputy assistant to the president" title. Trump restored the job as an "assistant to the president."