Breaking his silence to a London Sunday newspaper yesterday, Mr Cox, 51, a literary agent who worked with Linda on a vegetarian cookbook, said the supposedly idyllic marriage between Linda and Paul was not as rosy as it seemed.
"There were moments when Linda would feel deeply unhappy and depressed about her marriage," he said.
"Every marriage has its ups and downs, of course.
"In her low moments, the idea of leaving him did cross her mind, but she immediately rejected it. Her family was the most important thing and there was no way she'd give them up. At the low points, she did feel trapped.
"When I started to learn all this, I was a bit dazed because I thought this was Britain's happiest marriage."
Although Mr Cox found Sir Paul charming and charismatic, he claimed the star had "a darker side" and could be very controlling. "He bossed her around."
It is understood Linda does not refer to domestic abuse on any of the 19 tapes she made.
But Mr Cox recalled: "Occasionally I'd find Linda in tears, obviously distressed."
It is understood a judge could demand Mr Cox play his tapes in court. Ms Mills alleges Sir Paul was violent towards her during their four-year marriage. He has vigorously denied her claims.
Mr Cox told how he grew close to Linda between 1987 and 1989 during frequent visits to the McCartneys' estate in Peasmarsh, East Sussex.
"I didn't warm to Paul," he said. "There was an awful coldness about him. His eyes were deader than any I had ever seen. But Linda and I hit it off. She had this aloof image but I found her the opposite �?warm and caring."
Mr Cox also recalled Linda's varying moods. "Some days she would be terrific and other days she would be depressed and wouldn't want to do anything."
There were times, however, when no amount of jokey cajoling would deliver Linda from her profound gloom, and Mr Cox learned to recognise the signs.
"She would be outside the house to greet me because she could hear the car coming down the drive," he said. "I could tell within seconds if she was upset. Sometimes she would put a brave face on but other times she was in tears."
Privy to the marriage's many intimacies even some of the McCartneys' most trusted advisers were unaware of, Mr Cox said he came to the conclusion Sir Paul kept his wife on a "tight leash �?like a caged animal".
"She didn't have ready access to money. I would often lend her a fiver or a tenner for groceries."
For all his wealth and celebrity, Mr Cox asserted Sir Paul was "frustrated". Even Linda, he said, referred to him as "such a frustrated man", but didn't say why.
"I suggested he should go into politics," Mr Cox said, "but Linda said he would do that only if he could be prime minister."
"Whatever the strange dynamic of their relationship, Linda was the only one Paul could open up to," he said. "She was like a mother to him. I have no doubt she loved him enormously, despite their problems."
http://www.news.com.au/dailytelegraph/story/0,22049,20664782-5006002,00.html
(I think it's a shame that the truth will probably never come out about Paul McCartney, and no one will be the wiser, because of all the hush money passed around.
Certainly, IMO, Heather Mills is a bit daft, BUT, she did specify exactly what he did, and he did abuse her just as he did Linda his first wife.
The two sides, (dual Gemini Sun) of Sir Paul.........two "distinct" sides of him, one is not very nice either.
I just noticed he has ALGOL conjunct exact, his M/C, the very soul's entry into the world: * I suppose it also showed his mother's demise at his birth?
Algol conj. MC very close, within minutes is very strong in his chart.
What you see is NOT what one gets in Sir Paul......