Most of us navigate quickly past the come-ons. But for some who are enticed to open these cyber doors, one click can ruin their lives.

But even the affair did not satisfy his addiction. "I had no idea what I was up against … Internet pornography is the crack cocaine of sexual addiction," said Leahy.

Cheap, But at a Cost

On the Web, you can see plenty for free. Those in search of hard-core porn pay from $50 to thousands a month.

But he's a textbook example of the guy always looking for the next high, the next fix, and didn't care when he broke the law, although he wouldn't say how.

All these men live in a shadow world, insisting they're just normal guys. Which means anyone of them could be your husband, your brother or even your son.