Ulster Unionist Health Minister Robin Swann has said that his former party leader was right to resign from a Stormont committee after he breached lockdown rules.
Mike Nesbitt stood down as deputy chair of the Committee for the Executive Office but is continuing as a Strangford MLA.
The Sunday World reported that he had visited a female friend in Portballintrae.
Mr Nesbitt (62) admitted making some "very poor decisions" and confirmed that he had been living apart from his wife, Lynda Bryans, for four months.
He also expressed his regret and remorse for flouting lockdown regulations.
Asked about his colleague's breach of the rules during a press briefing at Stormont, Mr Swann said: "Mike has resigned as vice-chair (of the committee) and I think that was the right thing for him to do.
"In my opinion, there is no person, no position or no point of privilege that is above the guidance and the rules and regulations as to how we combat Covid-19 in Northern Ireland.
"I know that Mike, as a man of integrity, for the reasons that he did flout the lockdown... I know it weighed heavily on his mind and he took the actions that he did."
Mr Nesbitt told the Sunday World: "Since late January, before lockdown, I have been living alone in a rented room in accommodation far north of Belfast.
"Recently I have stayed occasionally in a three-bedroom property occupied full-time by a female friend.
"This has been a stressful and difficult period for me and unfortunately I have made some very poor decisions.
"I am remorseful and apologise. I shall not return during lockdown."
In March the former UUP leader spoke movingly of the death of his 93-year old mother, Brenda Nesbitt, known as Paddy.
When Mr Swann announced he was resigning as UUP leader last October, Mr Nesbitt considered standing for the leadership again but later ruled himself out due to a heart problem.
UUP leader Steve Aiken criticised his Strangford MLA.
"Breaking the regulations is unacceptable, no matter who you are. Mike has made a huge mistake and he has accepted what he did was wrong," he said.