EXCLUSIVE - The "other woman" in National leader Don Brash's alleged affair has spoken for the first time of the "traumatic" impact of the allegations - and of her long relationship with Brash and his wife.

Multi-millionaire businesswoman Diane Foreman has also told the Herald on Sunday that her husband, Bill Foreman, is standing by her and that they love each other.

The Herald on Sunday can also reveal today that:

* The alleged affair began before Dr Brash was elected to Parliament.

* He returned home to Auckland and confessed to his wife Je Lan more than a week ago that it would be made public.

* There is speculation that other details of Brash's private life will be made public.

The new revelations are likely to add to pressure on Brash, as senior party figures tense for further details of his private life to emerge.

For days the National leader has been linked to Megan Williams, a Hawke's Bay businesswoman. Last night she confirmed that they had a relationship while both parties were single.

Yesterday, Brash denied there were more secrets but offered his closest confirmation yet of the affair with Foreman. "I have nothing else to hide," he said. He said that the "else" should not be taken as confirmation.

The Herald on Sunday has learned that Brash began seeing Foreman when he was governor of the Reserve Bank.

A close friend has told the Herald on Sunday that Foreman was influential in encouraging Brash to stand for Parliament.

The friend said the affair was discovered before the 2002 election, and Brash told wife Je Lan that his relationship with Foreman was over. Despite this, Foreman continued to communicate and offer advice to Brash.

Brash became convinced 10 days ago that the affair would be made public after he was barracked by Government ministers in Parliament. He returned home to Auckland and told Je Lan last Saturday that the affair would be made public. On Tuesday, he told his caucus that the allegations would be made.

Yesterday Brash told the Herald on Sunday: "It was not easy, I have to say. It's very important I put that to one side and continue in my role."

Asked how Je Lan was coping, he said: "She's keeping her head down."

Last night, Foreman was still refusing to confirm or deny that she had been involved with Dr Brash other than as friends. "...You need to know I've known both the Brashs for a very long time, which pre-dates any involvement in politics or my involvement in the Business Roundtable," she said.

"I've known Je Lan and Don for years. That's why I'm finding this whole thing incredible. Everyone seems to be taking a huge slice of speculation about my life.

"I make no secret of the fact I have known the Brashs for many, many years. We have shared meals on many many occasions, shared barbecues.

"It's just amazing how people think they know so much more about my life than I do.

"I have had numerous dinners, lunches, breakfasts... ah, maybe not breakfasts, with both Je Lan and Don."

She said TV3's decision to name her last week was "a great shame". She wanted the public to remember that though she had been linked to the National Party leader, there had been no proof. She "could not" and "would not" talk about the allegations of an affair.

"I'm not enjoying this. I'm a private person. I'm not enjoying the media scrutiny."

However, she also refused to deny that there was any truth to the claim.

Foreman said that her relationship with her husband, Bill, was rock solid.

"Bill and I have been married for a very long time. My marriage is absolutely fine. I've got the most amazing husband who is and continues to be hugely supportive."

Since arriving at one of the couple's homes in Port Douglas, Australia, last week, Foreman said she had become aware through friends of the impact the news was having in New Zealand.

"The things I've learned most through this whole experience is that good friends are very dear. I've had incredibly good support from lots of people who have been fantastic."

But the distance had also made her keenly aware that returning to New Zealand was going to be difficult.

"I am a mother of four children, small children, and they have to live in this town, too.

"I love New Zealand, and I find this is a really difficult situation."

Her children, she said, were finding the situation "extremely difficult".

Foreman rejected claims that her position as deputy chairwoman of the New Zealand Business Roundtable could have undue influence on Dr Brash.

"Yeah, right," she said, sarcastically. "My comment to that would be, 'Yeah right'."

She said: "The Business Roundtable is about wanting better policy.

"It's a policy organisation. I don't really see where the correlation is, myself."

It is believed that Foreman was forewarned that the allegations would become public this week, and she flew out to Port Douglas early, to be joined later by her husband.

"The important thing for me to remember always is I have children, and this is very very traumatic on my family," she said.

"For something that is totally unsubstantiated - it's been tough. I'm finding this media intrusion in my life exceedingly difficult to cope with."

Last night Foreman's family - including her four children, Bill and her parents Frank and Shirley Linney - issued a statement expressing their support of her.

"We all love and respect her dearly and are deeply offended and distressed by the comments that have been made about her and our family," the statement read. "We are a close and united family." Foreman, her voice occasionally breaking, admitted to the Herald on Sunday that she was struggling with being in the public eye.

"I think it's grossly unfair my life is being subjected to this kind of scrutiny," she said.

"I think I live a pretty boring life, don't you?"