Picture this: you are in your mid-twenties and you meet the love of your life. You spend every day together and are rarely apart; your life together is an extended date. You ride motorcycles, fly antique aeroplanes, sit side by side in rocking chairs drinking beer and watching the sun set. Sometimes you'll get in the pick-up truck, go to flea markets, collect cast-iron toys.

You're young. This person is older than you - 23 years older - and looks out for you, cherishes you, makes you feel safe. You plan to spend the rest of your lives together, even though neither of you make plans because you live in the moment. Then, after 31/2 years, it stops.

He dies, a messy, drawn-out death from incurable cancer. For the last six months of his life you take care of him. You watch the person you love, who was so virile and active, fade away, and you are helpless. At 27 you become a widow. Do you ever recover? Not really. You move on with your life, but emotionally you stay frozen in time. Imagine too that this person is a film star, mourned not just by you, but by the rest of the world. An icon whose image is synonymous with speed, freedom, American cool and low-key glamour; a private man whose death only enhances public curiosity. If you turn on the TV and one of his films is on, you switch channels. You can't watch or you'll break down. If you open a magazine and his face stares out at you, you flip away from the page. If you're in Times Square and his image looms from a billboard, you stare at the ground.

For Barbara McQueen, this narrative has been her life. It's easy to understand why, 26 years since Steve McQueen's death, he's still haunting her. It wasn't just the films - The Great Escape, The Thomas Crown Affair, The Cincinnati Kid, The Getaway, Papillon - that cemented his iconic status. It was the aura, the fact that he lived on his own terms, trusting nobody, known by only a select few.

Barbara McQueen rarely speaks to the press. She lives in the true wilderness area of Montana, where it seems a grizzly bear could emerge at any second. Turning into the driveway of a modest blue farmhouse is a handmade sign on the fence that reads "If You Go Past This Point You Better Have a Damn Good Reason" - a favourite staying of Steve's. Despite the warning, the house is whimsical and playful. Fairy lights are strung out on the porch above the rocking chairs the McQueens used to have at their house in Santa Paula, California, and a stuffed teddy bear hangs out of a second-storey window.

She greets me barefoot, wearing pink Mickey Mouse pyjama bottoms, Gucci rose-tinted sunglasses, a black fleece pullover and diamond studs in her ears. She is tall and slim; her shiny black hair with a reddish tint is pulled back in a ponytail. A headband conceals the fringe that a girl friend recently talked her into cutting after they had both had a little too much to drink.

I wasn't sure what to expect: the photos in her book are from her modelling days in the late 1970s, and then with McQueen while she was in her twenties. Now, just past 50, she has, like McQueen himself, remained ageless. When I tell her she looks virtually the same - down to how she wears her hair - she says it's the make-up. She is the type of woman who will chop wood in pink lipstick. Her voice is deep and serious, but she laughs easily and has a girlish manner. Friends call her Barbie. She seems both naive and worldly, willing to let down her guard - but only so much.

Her home resembles a doll's house, packed with antique toys, second-hand furniture; many of the items belonged to Steve. There is a cigarette machine at the bottom of the stairs, a bed in the guest room, two saddles - one in the kitchen and above it hangs the horsehair bridle - a wedding gift. Everywhere you look, you feel his presence.

Barbara's bedroom could be the bedroom of a 16-year-old girl, except she instructs me not to trip over the rifle that peeks out from under the bed. Over the bed is a framed poster of a young Steve McQueen, printed for the November 2006 auction of his estate, at the Peterson Automotive Museum in LA. Hundreds of personal effects - motorcycles like his 1929 Harley Model B and 1934 Indian Scout, clothing, toys, even a Master Charge credit card that used to belong to Barbara - were auctioned off.

She says it was liberating. "It was great stuff but I was worried about it - I had all of it in the house in Arizona. And it was a classy auction." The Persol sunglasses he wore in The Thomas Crown Affair went for $70,000. "Can you believe that?" she says, genuinely baffled. Fifty per cent ?of the money went to the Boys' Republic, the reform school Steve attended in his teens. Some accused her of cashing in, exploiting his legacy. "I got plenty of money - and I don't care what people think. I earned it - I deserved it. I don't care. You couldn't pay me - what I did with Steve when he was sick? I earned it."

So why did she wait so long? Purging the memory wasn't the motive, nor was seeking out the notoriety. Turning 50, she felt it was time. It was the age Steve was when he died. She writes: "It's as if a veil had been lifted."

She also admits that the process of dealing with it hurt too much. Going through the items, letting go of them? she couldn't talk about him. And it's still difficult. She has never spoken about him at such length, and the memory is still raw. Yet she has been remarried, happily, for 16 years. Her husband, Dave Brunsvold, must get frustrated with the ghost in their marriage. How does he feel about the picture of McQueen hanging over the bed? Barbara laughs. She says this house is her place to hide out, whereas he prefers Arizona. She says sometimes she'll goof and call Dave "Steve", then admits, yes, it's hard for him. Later I'll meet Dave, and he is similar to McQueen in manner and temperament. He is protective of Barbara, slightly aloof, and in nobody's shadow.

We settle in downstairs. "The only thing I won't talk about is Steve's death," she says. "I don't think it's anybody's business. He's got children and grandchildren and they don't need to know the truth."

She is still close to Chad McQueen, Steve's son, and was close to Terry, his daughter who passed away in 1998 from a genetic metabolism disorder. While filming The Hunter, Steve had a persistent cough. When filming stopped, Barbara made him see a doctor. The diagnosis was terminal. A year later, Steve died after surgery to remove a couple of tumours in his neck and abdomen. The last six months were spent in Juarez, Mexico, where he was getting alternative treatments. Why, with all the money available for cutting-edge treatment at Cedars-Sinai hospital, near their California home, would he choose Mexico?

"Mexico was his last hope for the alternative medicines. He said to me when he found out he was sick, 'Okay, honey, what do you want to do? You want to have some fun - go live in the desert, travel, or try the alternatives.' And I'm in love - of course I say I want to try the alternatives."

Did she trust what they were doing? She laughs and gives me a look. "You don't talk Steve McQueen out of anything. What he wants to do, he's gonna do." Often without realising it, she speaks about him in the present tense. "I could tell the hanger-onners - people who were out for the bucks. But if that's what he needed to do, that's what we were gonna do to make him comfortable." In fact, he had been to Cedars and conventional medicine had written him off. "I didn't know it, but they'd told him he had three to six months to live. That it was incurable."

Mesothelioma is an aggressive asbestos-related cancer. Nobody knows for sure how he got it, but it's believed it came from when he was in the merchant marine (in ?1946-7). One of his duties was to clean and scrape the ceiling in one of the old ships. There's also the possibility that it could have come from racing. The fireproof cloth that goes under the masks was made of asbestos.

"They told me five to six years," Barbara says, sounding angry. After he passed away she went to Cedars and let them know she was livid. "We could've gone to the desert if I'd known it was that bad. That pissed me off."

If they hadn't tried to protect her and told her the truth, she says she would have chosen differently. "Had I known it would be three to six months, I'd have said to him, 'Let's do whatever you want to do - it's your story now.' But I got bad information. He says, 'What do you want to do?' I wanted to do anything I could to get a couple more years." Just then her voice becomes stern. "Don't delve on the death part too much - it freaks me out." She pauses. Did he have fear about his death? The phone rings and Barbara jumps up. "Perfect timing! I don't want to talk about that."

It's her husband, Dave. He's driving on his way up from their home in Arizona. When the call is over she sits down again. "The other day a girl friend called me and said, 'You have to watch Thomas Crown, you have to see what Faye Dunaway was wearing.' I started to watch and I was wailing." She doesn't know exactly why she was crying so hard, but she didn't recognise the man on the screen. She doesn't see McQueen as a movie star, and never has. "I didn't marry a movie star. I married a guy named Steve who had a scruffy beard and long hair and liked to ride around in pick-up trucks and drink beer. That was my guy."

By the time they got together, McQueen wanted to be nondescript and unrecognised. But if it went on too long and someone gave him that everyday snub, all of a sudden he would turn into Steve McQueen the movie star. "But it didn't last long," Barbara says, dismissing his need for attention. "They could gush over him for a little bit and then it was done. We had a really simple, easy life."

How they met, in 1977, is described in the book. After seeing her photo in a Club Med ad, McQueen devised a way for them to meet: he arranged through her modelling agent to audition Barbara for a role in his new movie. She flew out to LA, thinking she was meeting Paul Newman. "I didn't know the difference. I saw The Towering Inferno in high school - they were both in it." The meeting took place over lunch at the Beverly Wilshire hotel, where he was living at the time. "In walks this grizzly, gruff man and the first thing he said was, 'My, you're tall.' I'm 5ft 10in and we looked eye to eye - and we sat down and he ordered two beers with ice. That was his deal, he always had to have two of everything. I think it was something from his childhood."

Barbara knew right away that she would marry him, even though during their initial meeting she didn't say a word. The following day she was by the pool at the hotel in a bikini and he appeared standing over her. He had his two beers and took her to the sauna. Everyone was kept out while he grilled her about her values and personal beliefs. "They were really personal questions: what I thought about this and that, my family?" Was he auditioning her as a girlfriend? "Honest to God, I have no clue. Women were swarming him. He asked if I wanted to have dinner. There was an instant attraction: he had something that just meshed. I've never had that before."

Later that evening when she went to his room for dinner, he opened the door and two blondes were in the room. "These chicks turn around - this was Steve McQueen, the movie star - everything was gold, white shirts, huge tits, tight pants. I start to walk away and he grabs my arm and says they were just leaving, and he kicks them out."

It was the July 4 weekend. After dinner they got in his car and drove up the coast. When they got to a motel, McQueen handed her a T-shirt, socks and a toothbrush and made her floss her teeth. "The rest is history," she says.

The scenario is not unfamiliar. A young, pretty model and an older, charismatic Hollywood actor. But what distinguished this encounter is that McQueen was notoriously distrustful. He was known to test people - to assume everyone was trying to con him. But with Barbara there was an immediate trust and intimacy. Other than a few paparazzo shots and publicity stills, in his last five years he didn't let anyone other than Barbara photograph him.

He allowed himself to relax in front of her lens because he didn't question her motives. "I didn't want anything from him. He felt that." Why was he so distrusting? "His whole life he'd been screwed by people. Stuff that happened in his childhood?" She doesn't finish the sentence and instead tells a story about his need for reassurance. "He didn't like me to work. But once, I had to take an assignment and I went to San Fran. I was ready to go to bed and he called me and said, 'Honey, I don't feel good. Can you come home?' I'm like, 'Now?' He's like, 'Yeah.' So I got home at 3am and he was fine! I guess he just wanted to test how much I cared."

Unsure about how having revealed his insecurity would be interpreted, she adds: "Everyone's insecure. I got tested constantly. Now I understand it. Then I didn't, but if you love someone - I could hear it in his voice - he needed me."

When Barbara decided to publish her archive of photos and co-write the manuscript, she knew she would only tell the loving and kind side of Steve. But some of the stories hint at a darker side, a complexity that is not explained.

The Steve McQueen who was difficult to live with and demanding on set is not on the page. She mentions his ego but only teasingly. By the time she "got him", he had nothing to prove. He had found someone he could be happy with. Someone with no ulterior agenda. "He liked that I didn't know he was a movie star. It took a long time to figure out, 'Oh, this is what you do.' We never watched his movies or did anything in Hollywood."

Surely they argued about some things? "He didn't argue with me. He had a temper, but not with me. He treated me really well. I heard stories about his other wives but he never laid a hand on me. He left all that crap behind him."

McQueen had been married twice before: to his first wife, Neile (with whom he had his children), from 1956 to 1972, then to Ali MacGraw, his co-star in The Getaway, from 1973 to 1978. Was there acrimony over his legacy? "I'm not going there," she says. "I will not talk about the ex-wives, although Ali MacGraw is a very wonderful woman.

"People take liberties when they write about him," she says, referring to the countless books and documentaries. "He was a gentle person. He was my husband and lover, and we were together for four years. He was really vulnerable. He put on a strong front." When asked why people are still obsessed with him, she shrugs. "He was this beautiful, magnificent man. A hunk. And he screams charisma."

As for what drove him, she thinks everything stemmed from his childhood. "I was adopted and wanted to find ?my birth parents and he said, 'No, don't do that, you'll only make yourself miserable.' He tried to find his father, and when he found him he was dead. His mother died when he was, I think, with Ali, and he never had much contact. It scarred him for life. Thank God she put him in Boys' Republic - that probably saved him." Steve McQueen was born in Indiana and raised by his uncle in Slater, Missouri. His mother had left him but reappeared several times, ?and when Steve was 12 he was taken to live with her and his abusive stepfather in California. Soon afterwards he ? was placed in the Boys' Republic, a "home for wayward boys". McQueen never knew his father, who left when ?he was six months old. It's been written that he was a ?stunt pilot for an aerial circus and that Steve's attraction ? to flying was a way to connect to him.

Barbara and Steve's days were simple. He would get up, have coffee, read the papers, feed the animals - go flying, maybe go downtown to a Chinese restaurant. He had plenty of money but was seeking a less complicated existence, so they lived in smaller houses and, for a while, in an aircraft hangar.

McQueen would be in his late seventies now. After his death, Barbara went to her house in Idaho. She was drained. She began dating someone else and, even though that relationship lasted four years - the same amount of time she was with Steve - she was still, in her mind, married to him. Does she think about how her life with him would be now? "If we'd still be married, we'd have half a dozen kids, be living on the ranch. I try not to think too much about it."

She keeps his name because he told her to. "When we were married, he was getting skinny and I thought something might be wrong. He said, 'Honey, you're a McQueen, you earned that name, you keep it.' " Did he know his legacy would be this strong? She pauses. "I think so."

There is a trunk that used to belong to him in a corner. She hasn't opened it and doesn't know what's inside. "I've had times when I've been alone and found something I didn't know I had - I break down on my knees, wailing about how much I miss him." She begins to cry, goes upstairs. When she reappears she tells me our conversation is digging up a lot of feelings. "I keep myself extremely guarded." It doesn't seem likely that she'd have been in therapy, and when asked, she responds without hesitation: "No! Budweiser ? therapy, that's it. My therapy's the country - the land. Crying is good, but I refuse to do it all the time. Steve wouldn't want me to do that. He taught me strength. Keep your chin up, don't let anyone fool you. I had a couple of months watching someone die. Being there 24/7 - it was the long goodbye. He always said, 'Be strong, honey - it's inevitable, it's going to happen.' "

So much of his world became her world, even before he got sick.He was the first person to turn her on to Kiehl's beauty products. He took good care of his hair. And he had lotions for his face. Even when he looked his scruffiest he was vain. "Let's just say he was very clean," she says, laughing. "He had great hygiene." She still uses the same brand of shampoo he used.

The talk turns to her plans for the summer. She's going to learn clay-pigeon shooting and work on decorating the house. She might put a target at the back of the garden and learn to shoot a bow and arrow. Her relationship with McQueen has shaped and defined her life. When she's alone, he's sitting on the sofa next to her. And because of him, she feels there is nothing she can't get through. Even an interview.

"He was a great teacher. He taught me so much. I don't take shit from anyone. He made me a strong woman. He made me what I am." s