"I know I still love her and I don't want to leave. It's not like I'm having an affair. I've been using the girls at the parlours for over nearly 20 years but, of course, it's not with the same woman all the time.

"I do have a couple of girls I like more than others but if I see them regularly, I start to feel guilty. It's not really about the person. It is just about a sexual release. My wife is still my best friend. She's the one I still sit down and have a cup of tea with in the morning. There's no way I want lose that."

Anderson's wife suspected he was having sex with someone else, but when he admitted it was prostitutes, rather than "another woman" in the classic sense, he was surprised at her reaction.

"I didn't think she would tolerate it or understand it but, in a way, she did. I think she was relieved that I wasn't having an affair," he says. "We talked about it at the start. She needed to be convinced that I wasn't in love with anyone else. Now we go out of our way to not bring it up. I would say she probably doesn't respect me in the same way. I guess it's perceived as a bit dirty, or a weakness. But I'm home with her every night and we have a great relationship as the parents of our kids."

Although their sexual relationship did restore itself to some extent, Anderson kept using sex workers and describes it with a nervous laugh as a "mild addiction".

"It's easy, the girls are young and they just give you their full attention. It's hard to pass that up once you know it's out there."

So difficult, in fact, that some men need to satisfy their urge for paid sex almost daily. As a trained social worker with the Men's Counselling Service, Chris Dawson sees a number of men from all social classes and says that, once it becomes a full-blown addiction, most want it to stop but feel they can't control it.

"It can get very expensive and they'll juggle finances like any other addiction. A lot of these people are self-employed and they're paid cash that doesn't go through the books. It's the white-collar worker, too. They might have a credit card on the side that nobody else knows about," Dawson says.

Why do they do it? "If they're getting satisfied somewhere else then they don't have to be intimate with their own partner. Most guys aren't good at intimacy."

When they eventually come to him for help, Dawson says it is because their relationship with a wife or girlfriend has become so problematic that they seek counselling to beat the desire.

And like any addiction, Dawson says that the motivation behind it can become muddied. Just as heroin addicts develop a love of the ritual-like needle preparation, Dawson says that prostitution addicts he has spoken to are often more excited by the planning than they are by the sex act itself.

"Some guys talk about how the sex itself doesn't actually do much for them. It's the planning and preparation. It's selecting the brothel, the drive to that building, the selection of the girl. It's anticipation. A lot of men try to deal with their problems by going to the brothels and then just walking out. That might be successful for a few days but then they have to score with someone. They don't like it. They carry a lot of shame. They can't control it," he says.

Ben Wilke, 31, doesn't necessarily agree. Currently "between girlfriends", the IT executive says that his use of prostitutes is purely a physical relief that he utilises when he can't get sex from anyone else.

"You can wake up in the morning and masturbate but it's not the same as really being with a woman and having her touch you."

Wilke has been known to occasionally pay for two girls at once to indulge a common fantasy, though says he has no need for any other role-playing games to inspire his sex drive.

"I just want to have sex, basically," he says. And he doesn't feel guilty. "If it's out there on offer, for sale, and it's a service that I'm happy to pay for, why should I feel guilty? I'm not desperate and I don't take risks. I'd never go to a street girl. At the brothels, it's nice and clean and you know they haven't got any STDs. It's safe."

Despite his projected image as a confident regular, Wilke says his first visit to a prostitute, when a long-term relationship broke down over four years ago, was intimidating." I was scared to death," he admits. Not so much because of what he thought the act itself would be like but because of what he thought it would say about him.

"I know I'm a fairly good-looking guy. My idea of the type of men that used hookers was the ugly, lonely fat guy who just couldn't get laid by anyone else.

"I could go out to a bar and pick someone up without too much hassle if I really wanted to. Paying for it and getting exactly what you want is just easier. You don't have to ring the girl up a few days later and take her out to dinner. I'm busy with work and trying to concentrate on my career."

Reclining in the darkened lounge area of Melbourne brothel The Daily Planet, working girls Heather and Emily have their own slant on why men pay for sex. When asked to sum it up in just one word, Heather comes up with "safety".

"Sexual safety, commitment safety, emotional safety,"

Emily agrees. "Their anonymity. They know that they're not going to be walking down the street with their friends or their girlfriends and we're going to walk past and say hello. Health-wise, we have to provide a certificate to work here.

"You don't go out and meet someone and in the middle of foreplay show a certificate that says you're clean. Plus, they won't get criticised, no matter how bad they are. That makes them feel good about themselves."