Republican Rep. Matt Rosendale says he'll retire from Congress after slapping back at rumors he got a staffer pregnant and ending a run for Senate after just a week

Rep. Matt Rosendale will not be running for re-election in the House after a failed Senate campaign and rumors swirled that he had an affair with a staffer. 

The Montana Republican blamed 'death threats' and 'false and defamatory rumors' for his decision to leave public office. 

'I have been forced to have law enforcement visit my children because of a death threat against me and false and defamatory rumors against my family,' Rosendale said in a statement.

'This has taken a serious toll on me, and my family,' he went on. 'It has caused a serious disruption to the election of the next representative for MT-02.' 

Matt and Jean Rosendale (pictured earlier this month as he filed to run for US Senate) moved lived on a ranch in Glendive, Montana for over 20 years, before deciding in 2020 to relocate to Great Falls. The couple decided to make Montana their home because they 'love and share' the state's values are that 'faith, family, and community are still important

'In the best interest of my family and the community, I am withdrawing from the House race and will not be seeking office.' 

Rosendale had been locked in a primary challenge against Tim Sheehy for the Senate seat currently occupied by Democrat Jon Tester. 

But national Republicans came out swinging against him - and Sheehy had clinched key endorsements from the Senate GOP's campaign arm and former President Donald Trump. 

The Montana Republican, 63, was one of eight Republicans who voted to oust former Speaker Kevin McCarthy.  

Rosendale then left the Senate race just one week after officially entering and jumped back into the race for his House seat. 

Matt Rosendale's family are standing by him after an ex-senator claimed he dropped out of the US Senate race because he 'impregnated a 20-year-old staff person'. His wife Jean, pictured with Rosendale and their children, is supporting him to pursue legal action and claims the family has urged the Congressman to 'fight'

But rumors spread throughout Capitol Hill and Montana politics that he had a sexual relationship with a staff member. 

Last week Rosendale's wife hit back at the allegations that he impregnated a staffer as 'false' and 'political mudslinging' as she reveals the family 'stand by him'.

Former Democratic Sen. Heidi Heitkamp had alleged there was a 'rumor' that Rosendale, 63, dropped out of the US Senate race because he 'impregnated a 20-year-old staff person'.

The Montana Republican's camp furiously denied the allegations, claiming they were 'false and defamatory', and on Tuesday his attorneys filed a litigation hold notice against the North Dakota Democrat.

Jean Rosendale, the lawmaker's wife of nearly 40 years, has now addressed the allegations, claiming the rumor is a 'disturbing lie' and '100 per cent false'.

She told Nonstop Local: 'We stand by Matt and have prayerfully urged him to continue the fight.'

Rosendale withdrew from the Senate race earlier this month after Donald Trump backed his opponent. He cited a 'lack of resources' and said that with the former president's endorsement the 'hill was just too steep'.

Former Senator Heidi Heitkamp (pictured in 2018) shared what she referred to as a 'rumor' about Rosendale during a podcast appearance on Monday. She said there was 'gossip' that he had impregnated a staffer amid an extramarital affair

Jean Rosendale, the lawmaker's wife of nearly 40 years, addressed the allegations on Tuesday, branding the rumor as a 'disturbing lie' and '100 per cent false'. Jean, pictured with her husband, said the remark was 'political mudslinging at its worst'

Heitkamp, during an appearance on the Talking Feds with Harry Litman podcast on Monday, claimed: 'There's a reason why Rosendale backed out of that Senate race. The rumor is that he impregnated a 20-year-old staff person.'

The one-term senator referred to the allegations as 'gossip' and did not provide any evidence to support the claim, but added that she predicts the GOP 'may lose a member in the next couple days.'

Ron Kovach, a spokesperson for Rosendale, has denied her allegations, telling DailyMail.com on Tuesday: 'This is 100 per cent false and defamatory and former Senator Heitkamp will be hearing from our lawyers soon.'

Now, Rosendale's wife Jean - echoing Kovach's language - has reinforced the family's position, telling Nonstop News that 'these lies are 100 per cent false' and 'political mudslinging at its worst'.

She said that after 14 years in public service, the family has become accustom to a 'certain amount of attacks on Matt for standing up for what he believes in'.

'But this disturbing lie about our entire family is truly political mudslinging at its worst and everyone should be offended by it,' Jean stated, adding that the family is supportive and encouraging to fight back.

Rosendale's lawyers have taken action against Heitkamp and, according to the news outlet, on Tuesday sent a letter stating they want 'corrective action' to be taken.

The litigation reportedly asks for relevant documentation to be preserved and is a 'notice of potential future legal proceedings'. 

Republican Congressman Matt Rosendale (pictured in the Montana State Capitol on February 9 this year) has denied an accusation that he dropped out of the US Senate race because he impregnated a 20-year-old staffer

Former Sen. Heidi Heitkamp (pictured in 2018), during an appearance on the Talking Feds with Harry Litman podcast on Monday, claimed: 'There's a reason why Rosendale backed out of that Senate race. The rumor is that he impregnated a 20-year-old staff person'

Rosendale, who is married and has three children, dropped his Senate bid on February 15, less than a week after he got into the race - only to see former Trump quickly endorse his opponent Tim Sheehy.

The hardline conservative said in a statement that with Trump's backing of fellow Republican Sheehy and a lack of resources, he was 'forced to calculate what my chances of success would be'.

Trump's endorsement came just hours after Rosendale had signed paperwork to formally launch his campaign on February 9. 

'As everyone knows, I have planned to run for the US Senate and to win both the primary and the general election,' Rosendale said at the time. 'However, the day I announced, President Trump then announced that he was endorsing a different candidate.

'I have long been a supporter of the President, and remain so. But I have been forced to calculate what my chances of success would be with Trump supporting my opponent.' 

Rosendale acknowledged that the 'race was already going to be tough' and that after further evaluation he determined, 'by my calculations, with Trump endorsing my opponent and the lack of resources, the hill was just too steep.'

He revealed he would be returning to Montana to be 'with my family and prayerfully consider what is next'.

Over the weekend, Rosendale filed paperwork to run for re-election to his US House seat, The Daily Montanan reported. Several other Republicans have already announced their intentions to enter that race, which is in a solidly GOP district.

Rosendale's exit from the Senate race avoids what analysts predicted to be a month-long fight within the GOP leading up the June 4 Montana primary.

Sheehy, after his withdrawal, said in a statement that Rosendale has held the line on reckless spending in DC and that he looked forward to working together with him to defeat three-term Democratic Sen. Jon Tester. 

Rosendale touts himself as being a family man who has 'dedicated his life to working for Montana'. He and his wife Jean are pictured with then-President Donald Trump in Oct. 2018

Heitkamp's accusation of the alleged affair has seemingly upset Rosendale, as evidence by his camp seeking legal action.

The representative touts himself as being a family man who has 'dedicated his life to working for Montana', according to his campaign website.

He and his wife Jean moved lived on a ranch in Glendive, Montana for over 20 years, before deciding in 2020 to relocate to Great Falls.

The couple decided to make Montana their home because they 'love and share' the state's values are that 'faith, family, and community are still important.'

Rosendale, a self-proclaimed 'avid hunter and outdoorsman', would open their ranch up to the Glendive community each years so that local 'kids, families, and veterans can hunt, camp, and recreate'.

He announced four years ago that he and Jean were relocating to be closer to their adult children, who were starting families of their own. 

'Those who know Jean and I, know that family is the most important thing to us,' Rosendale wrote on Facebook in 2020, sharing how they were 'blessed' to have raised their three sons in Glendive.

He said: 'We are a tight knit family, and like many parents want to be closer to our children (and hopefully grandchildren!). That's why, after much discussion and prayer as a family, Jean and I have made the decision to sell our home in Glendive and begin the process of relocating to be closer to our two sons and daughter-in-law in Great Falls.

'While we will always cherish our time in Glendive and all of our friends and neighbors there, we are excited to be closer to our children and for our family's next chapter!'

The press office for the Institute of Politics at the University of Chicago, where Heitkamp is currently serving as director, did not respond to DailyMail.com's request for comment on Tuesday.

Rep. Matt Rosendale is pictured filing paperwork to run for US Senate on Friday, Feb. 9, 2024, at the state capitol in Helena. He dropped his Senate bid on February 15, less than a week after he got into the race

Campaign volunteer Joey Grewell is seen putting up a sign for Montana Rep. Matt Rosendale's U.S. senate campaign during a Republican gathering, Friday, Feb. 9, 2024, in Helena

In Washington, Rosendale is among the House's most hard-right conservatives and a member of the House Freedom Caucus. He banded with seven other members of his party in October to oust Republican Speaker Kevin McCarthy. He supports Trump and voted against certifying the 2020 election.

Rosendale had said when he announced his campaign that he would be able to challenge Tester despite losing to him in 2018. Trump played a large role in that election, too, visiting Montana repeatedly to stump for Rosendale, who lost by about 3.5 percentage points.

'I've won two elections since then,' Rosendale, 63, told reporters on February 9 as he entered the race. 'And the most important thing is that my name ID and my trust factor is elevated dramatically. People know who I am.'

While a large contingent of conservative state lawmakers cheered Rosendale's filing, Daines issued a statement saying: 'It's unfortunate that rather than building seniority for our great state in the House, Matt is choosing to abandon his seat and create a divisive primary.'

But Republicans in Washington had worked to keep Rosendale on the sidelines, with leading members of the party supporting Sheehy as the party's best chance to topple Tester - part of their strategy to take control of the Senate by targeting a few vulnerable Democratic seats in the 2024 election. 

Sheehy, a former Navy SEAL who now owns an aerial firefighting company with extensive government contracts, is a political newcomer backed by Senate Minority Leader Mitch McConnell and Montana Sen. Steve Daines - the chair of the National Republican Senatorial Committee.

Former Montana Secretary of State Brad Johnson is also vying for the Republican US Senate nomination.

Rosendale (pictured with Jean in 2018) is among the House's most hard-right conservatives and a member of the House Freedom Caucus. He banded with seven other members of his party in October to oust Republican Speaker Kevin McCarthy. He supports Trump and voted against certifying the 2020 election

Tester, a political moderate, has held onto his Senate post even as Montana tilted increasingly Republican over the past several election cycles.

When he entered the Senate in 2007, Democrats held almost every statewide elected office in Montana, from governor and attorney general, to two of the state's three seats in Congress. Since 2020, that's down to Tester's seat.

Montana Democrats had relished the possibility of an ugly primary fight between Sheehy and Rosendale, which could have distracted GOP voters in advance of the general election and drained some of the party's campaign funds.

The race is on track to be among the most expensive in Montana political history. Spending on advertising by the candidates and outside political groups already topped $18million. 

An additional $95million in advertising has been reserved for the coming months, according to data from AdImpact, a firm that tracks political advertising.

Maneuvering by Republicans to increase their chances of beating Tester began last year when Republican state lawmakers proposed election rule changes that would have allowed only the top two candidates to advance out of the state's 2024 Senate primary. 

That likely would have kept third-party candidates off the general election ballot and could have tipped the election in their favor.

Past races for Tester's seat were close enough that some Republicans blamed third-party candidates for the Democrat's victories.