There's a stereotypical image of the kind of men who go to prostitutes. But how do they explain paying for sex?
Fred and Laura go on walks, take weekend breaks away, amble round markets and often have meals out.
They have a laugh together over things they've seen on TV. But they can fight and argue too.
In Fred's kitchen, while he prepares the evening meal, Laura sits and giggles, admitting it was a good job she wasn't the one cooking.
Like any couple they have their ups and downs. But they're not like most couples.
Fred pays Laura to spend time with him, and have sex with him.
They have been seeing each other for six years.
The debate about whether there's something wrong with buying sex, and whether it should be illegal, is heated and unresolved. Amid the debate, however, one question is rarely asked - what motivates men to pay women to sleep with them?
"We first met online on a message board," says Fred, who is retired, "and I asked her if she would like to spend the night in a hotel with me."
He says it was like a first date, "getting to know each other, sounding each other out."
"Now we know each other so well that Fred just transfers the money to my bank online before I come to meet him," says Laura.
Fred lives in a remote rural area and for many years he was a full-time carer, looking after his mother. He says he didn't have a chance to meet people - so decided to pay for sex.
"It really wasn't so much the sex as wanting female company and if you are not getting out and socialising then it is very difficult to think about how you're going to get that."
Robert has been married for many years.
"I ended up a highly sexed man married to a woman who really didn't enjoy sex - [or even] hugging, kissing and so on.
"She's an excellent, excellent partner. In every other way we got on like a house on fire, but just not in bed."
Robert squirrels away as much money as he can to buy sex.
"I wanted to hang on to my marriage," he says, "I wanted to do right as much as I could by my wife, so the obvious thing was to pay for it."
The ethical maze of prostitution
The idea that human beings could be for sale is ethically controversial. Yet sex workers often say they don't sell their bodies but, like other workers, simply put a price on their talents and skills. They argue that, if sex work was decriminalised and destigmatised, the associated problems would mostly disappear. Is there anything wrong with selling sex?
While Robert sees paying for sex as a way to preserve his marriage, Graham, in his 30s, thought it might be a way to avoid the complexity of relationships altogether.
For the first 30 years of his life, former civil servant Graham thought he would never be the sort of man who would pay for sex. But one weekend in Amsterdam he found himself walking the streets of the red light district with some men he had just met.
A girl beckoned them, but two of the men dismissed her. "We can get a better one," they said.
She turned to Graham. "You'll come upstairs with me won't you?" she said.
"At that time," Graham says, "I probably just couldn't see any barriers as to why I wouldn't."
He followed her to a red-lit booth and spent half an hour with her, chatting and having sex.
"It was amazing. It felt really romantic, it felt like we were condensing a relationship into just a couple of minutes."
Reflecting on his previous relationships and painful breakups, he wondered: "Maybe you don't need to do any of that. Maybe you can pay and have these just incredible moments of spontaneous, all over in half an hour… just… magic."
Simon, a shy man, has never found meeting women easy. At 29 he decided to lose his virginity by paying for sex. But he was never comfortable with his decision.
"I've read stuff on the internet that it's not good emotionally for women," Simon, who is in his 30s, says. But it hasn't stopped him regularly visiting the same woman over the last few years.
"I've got a high sex drive and it is not just that I enjoy sex, but if I don't have sex after a while, I feel terrible physically."
Simon prefers to see the same woman because he is more relaxed with her than he would be with someone new.
But although he knows her quite well, he says he is under no illusions.
"If I wasn't paying her, she wouldn't dream of having sex with me."
Simon has had a couple of girlfriends in the last few years and while in those relationships, he says he stopped paying for sex. He hopes to be in another relationship again one day.
"I just prefer that the woman I'm having sex with wants to do it, not for money, but wants to be with me."
More from the Magazine
Most people think of male prostitution as dangerous, degrading and exploitative work. But there are some who are attempting to reinvent it as a profession free of stigma by using all the tools of modern business. The escorts who want to rebrand male prostitution (2014)
And it's not just men who pay prostitutes to sleep with them. For some women, paying for sex is more convenient than cruising bars and clubs trying to find men. The women who pay for sex (2009)
Robert, however, is motivated by more than a need for intimacy. He pays for sex to satisfy his fantasies.
"I seek out interesting experiences - but I kid myself that this makes up for all those thousands of sessions of domestic sex that I can't have and never will have."
He describes himself as "a bit of an exhibitionist" and a "voyeur" and has arranged sex parties with groups.
Brian, who is in his 50s, says he is happily married. But he started paying for sex long before he met her. He says sex in his marriage lacked "a bit of excitement".
"Maybe I had been spoilt from seeing other women previously," he says, "when some of the sex had been very good. The sex in the marriage wasn't quite as good, shall we say."
In Fred's kitchen, we watched him fuss over dinner. He explained how he had known Laura so long, they often meet as friends. But if they go away for a holiday, he pays the going rate.
He admits he is more than a little bit in love with her. Does it bother him that Laura sees other clients?
"No, that's her job," he says.
After Graham's first encounter in the red light district in Amsterdam, he was keen to recreate the experience. He says the second time he paid for sex wasn't the same. The woman seemed "melancholy."
The third time put him off for life. He says the woman was cold and harsh, and the room felt like a doctors surgery.
"We had sex, but I looked down into her eyes and she couldn't focus. And I realised at that time I was having sex with a drug addict. I felt just ghastly.
"I walked down the stairs, outside in to the Amsterdam night. All this lustre that I'd seen before, everything had seemed a little exotic, suddenly seemed dirty."
Brian says he leads a double life. His family and friends are kept in the dark about the other side of him.
"I don't think they would like to think that I was getting involved in visiting working girls for sex because it's not the thing that a respectable person does to be honest.
"And to all other intents and purposes, I am."
Some names have been changed.
Why Men Pay for Sex is broadcast on BBC Radio 4 on Monday 25 August 2014 at 20:00 BST. Or listen afterwards on BBC iPlayer.
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