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."
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.
"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.