Alan, a well-respected medical specialist, has a beautiful wife whom he loves deeply, but he never has sex with her. When she shows the slightest interest in intimacy, he picks a fight or finds some excuse to avoid her.
Sometimes if he senses she is going to be in the mood, he masturbates beforehand, leaving his wife hurt and confused when he doesn't want her.
It's hard to believe, but Alan, who is too ashamed to use his real name, is a sex addict.
Until recently, the Pennsylvania 42-year-old has led a double life, sneaking off to the computer for self-gratification. At first he looked online for erotic images and videos to get an escalating excitement he calls "the haze, the high and the full numbness."
But soon that wasn't enough, and he needed to watch a live person, or have phone sex -- up to three hours a day, sometimes "grabbing a sneak peak" from work. Eventually, Alan had an affair, texting about sex non-stop, and he could no longer hide it from his wife.
"Some people don't think that sex addiction is a real addiction, but it is," he said. "The way my heart races when I start logging on to Web sites to the build-up. I can go here and go there. What it does, it gets you high and when you are done, finished, you are calm or numb. It's almost like self-mutilation. That's the way I feel, numb and not there, like a part of my body is not there."
Alan, who is now getting help in a 12-step program, is among an estimated 5 to 6 percent of all Americans who admit to sex addiction, most of them men.
The field is new in the psychiatric world, but has gained more attention since celebrities like actor David Duchovny, Major League Baseball player Wade Boggs and British comedian Russell Brand have confessed to sex addiction.
In the year since golfer Tiger Woods checked into a Mississippi sex rehabilitation clinic, the number of those seeking treatment has jumped by 50 percent, according to Robert Weiss, founding director of the Sexual Recovery Institute in Los Angeles, which opened in 1995.
The month after Woods went into rehab, the Sexual Recovery Institute began offering information sessions that have been drawing 35 to 50 people a week.
Its Web site has had 13,000 hits in the last 30 days.
"I don't think it's accidental," said Weiss. "Even those who don't ask for help are looking for information."
There has been disagreement in the scientific community over whether people can be addicted to sex in the same way as drugs or alcohol. Two characteristics of substance abuse are building up a tolerance over time and going through withdrawal when deprived.
The American Psychiatric Association does not even include sex addiction in its Diagnostics Standards Manual IV, although it is under review for the next edition.
"The reality is that with little research and no clear diagnosis, at least for now, the treatment one receives is dependent on who you get as a therapist," said Weiss. "We have a dearth of professional, well-researched training programs and institutes."
At present there are only a handful of large out-patient clinics and only about 900 therapists who have had some training or certification, according to Weiss.
Sex addiction, like over-eating and compulsive spending and gambling, is a process addiction -- a neurobiological arousal disorder that involves the interplay of the hormones serotonin, dopamine and adrenaline.
Broadly defined by the Institute for Trauma and Addiction Professionals, sex addiction is "any sexually related, compulsive behavior which interferes with normal living and causes severe stress on family, friends, loved ones and one's work environment."
Sex Addiction Like Gambling, Spending Addictions
A sex addict, like a gambling addict, "is not looking to win or lose," said Weiss. "He is going in with an intense fantasy -- his heart is racing, his adrenaline is pumping. They are in it for the intense, emotional arousal that provides them with a self-soothing, emotional calm. If you put yourself in a situation of danger, the response would be distracting, but it's soothing to them. They would say it's like being in a trance, being in a bubble."
The compulsive behavior is triggered by anxiety, and continues in a vicious cycle of stress, release and then shame, which ignites the anxiety again.
"It has an obsessive quality," said Weiss. "Like any addiction there is a loss of control. You think you will look for 15 minutes and end up looking for three hours. .A guy loses three hours looking for a prostitute in a car. They spend endless time online -- there's a name for it, 'face-hooked.'"
The least amount of time is spent on the physical and sexual -- the most is spent "looking and in pursuit," said Weiss.
The roots often lie in childhood.
"I have been acting out with pornography since the age of 13," said Alan. "As a child in a dysfunctional family, it was one way to sooth myself. I always tried to be in relationships with women but once the thrill wore off, I would go looking for that feeling again."
Alan also said he was molested at the age of 11. His father was a "rage-aholic" and his parents divorced as he approached the teen years.
"It starts with a basic core belief I am unlovable or undeserving of love in the first place," said Alan. "I have a total inability to be intimate. This is not about sex."
Many who suspect they are sex addicts, but are too ashamed to seek help, don't know where to turn.
"I can't control the addictions and I want help," one man from Houston, Texas, wrote ABCNews.com. "It's ruining my life because I put sex, masturbation and porn before my education and family. I am not normal and I need treatment. Sex is my cocaine and it's tearing me apart."
"I can't continue living a double life, seeking sex in dirty places," he said. "I need to get this under control."
The key to understanding why sex addiction is on the rise are the "three A's" -- access, anonymity and affordability, according to Weiss. He blames the rise in sex addicts on the Internet.
Online Pornography Led to Sexual Affairs
"If someone used sex to escape in 1992, they had to get up, get dressed and get to the subway to go to an adult bookstore -- that's what they had to do to get porn," he said. "Now, they pick up a phone, they have sheer access to the Internet with only a moment between what you want to do and doing it."
Such was the case with Sid, a 53-year-old teacher from Boston who was also afraid to reveal his real name.
His 23-year marriage fell apart because of an addiction to online pornography that led to an affair. Since February, Sid has been kicked out of his house, away from the wife he loves and his two teenage children.
"My life is a disaster," he said.
Sid was also exposed to pornography at an early age and was molested as a child at camp. That "acting out" continued with a male cousin. "I felt a lot of shame and guilt," said Sid, who is heterosexual.
"Before the days of the Internet, I would put on a baseball cap and go to the dirty little book store in the next town over," he said. "When the Internet came along, it just progressed and instead of going to the bookstore, I could point and click after my wife went to sleep. It's viscous freaking circle. I was meeting people online and having affairs.'
Several times, he tried to "clean it up," but each time he got stressed, he would go back. His wife caught him several times, finding photos on his laptop.
"My wife is crazy right now," he said. "I do love her."
The goal of therapy is to stop the behavior -- but unlike alcohol addiction, addicts cannot give up sex altogether. Programs target triggers, build social networks and require addicts to make a full disclosure of their affairs to loved ones.
About 80 percent of sex addicts seeking treatment stay with it for the first year, but there is a high rate of relapse, according to Weiss.
The day before Thanksgiving, Sid sent an e-mail to his parents, informing them of his "indiscretions" and why his marriage fell apart.
He also spoke again to his wife, revealing more.
"I am really tired of not being honest with people," he said. "This is a first step. I don't know what tomorrow will bring."
Sex addiction is "powerful," according to Sid.
"Look at Eliot Spitzer, Bill Clinton and Tiger Woods," he said. "It's easy for people to sit back and call then dirt balls, scum bags and be ostracized. But the bottom line is these people are suffering. I am not saying I couldn't have done more. We all make our choices. But when you are stuck being the same way, it's pretty hard for a leopard to change his spots."