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.
On Friday, Mr Trump paid tribute to Mr Porter, who quit his White House position on Wednesday.
The 29-year-old aide has recently been in a relationship with Mr Porter, a Harvard graduate and former Oxford Rhodes Scholar.
Mr Trump was reportedly not consulted when Ms Hicks helped draft an initial statement defending Mr Porter, reports BBC.