A speechwriter has become the second White House aide this week to resign amid allegations of domestic abuse. David Sorensen denies his former wife's allegations he was violent and emotionally abusive.
His departure comes just days after another Trump official, Rob Porter, quit over allegations of abuse from two ex-wives, something he denies.
The scandal has put pressure on Chief of Staff John Kelly, who has faced questions over what he knew and when.
Mr Kelly and the White House have both denied reports he offered to resign over his handling of the allegations made against ex-staff secretary Rob Porter.
The chief of staff initially called Mr Porter, 40, "a man of true integrity and honour" after allegations of domestic abuse involving two ex-wives surfaced on Tuesday. It is alleged that Mr Porter gave one ex-wife a black eye while another filed a restraining order. He denies both.
Speaking in the Oval Office on Friday, Mr Trump said: "We found out about it recently and I was surprised by it, but we certainly wish him well and it's a tough time for him. But Mr Trump did not refer to Mr Porter's accusers.
His comments sparked criticism from Democrats, with former Vice-President Joe Biden saying Mr Trump had downplayed the allegations against Mr Porter.
"That's like saying: 'That axe murderer out there, he's a great painter'", Mr Biden said.
According to CBS News, Mr Porter approached White House Counsel Don McGahn in January 2017 to inform him his ex-wives might say unflattering things about him to background check investigators.
In June 2017, Mr Porter's preliminary file was sent from the FBI to the White House security office, containing the abuse allegations.
In November, Mr McGahn received a call from an ex-girlfriend of Mr Porter alleging physical violence by the aide.
Mr McGahn told the White House chief of staff there was an issue with Mr Porter's security clearance, although he was vague, reports CBS.
Mr Porter told Mr Kelly his ex-wives were saying false things about him. A White House spokesman said on Thursday that Mr Kelly did not realise the extent of the claims until a photo of one of Mr Porter's former wives, Colbie Holderness, suffering a black eye, emerged on Wednesday.