Joe never hit, kicked or slapped his wife. Because of that, he never considered himself a domestic abuser.

That hardly mattered when his wife earlier this year told him she was filing for divorce and demanded that he move out of their O'ahu home. For her, the years-long emotional and mental abuse had become too much.

"I was oblivious to the fact that it was domestic violence," he said.

Today, Joe (not his real name) is voluntarily attending a domestic violence intervention program at Catholic Charities Hawai'i. He realized — too late — that the psychological abuse he was inflicting on his wife and their two children was just as damaging as if he were beating them physically.

In some ways, the emotional scarring can be more profound and longer lasting.

"I came to the full realization that I hurt them deeply," said Joe, who asked that his real name not be used because of possible implications to his career. "I didn't want to be that guy anymore."

Joe is among the thousands of Hawai'i residents who are current or former domestic abusers. Most are men, though prosecutors are seeing a small but growing number of women.

Some offenders deny they are abusers, even if a court says otherwise. Some rationalize their behavior, saying the violence was warranted. Some, however, acknowledge they crossed the line.

Anyone found guilty in Hawai'i courts of committing domestic violence is ordered to complete an intervention program as part of their sentence, which also can include jail time or probation. A minority of abusers, including Joe, realize on their own that they have a problem and voluntarily seek help.

One of the most perplexing aspects of domestic violence deals with the motivation behind the abuse. Why would anyone resort to beating a loved one?

Most experts say such behavior is learned. Offenders believe turning to abuse to maintain power and control over a woman is OK because they see it all around them — in movies, video games, television programs, other relationships, social institutions, advertising.

In many cases, the offenders also grow up with it. As children, they see one parent abusing another, and they often resort to similar behaviors in their own intimate relationships as they become adults. In that fashion, the cycle of violence is passed from one generation to the next.

"Babies are not born to be violent," said Ray Torres, a Child & Family Service domestic violence specialist who conducts intervention courses for offenders on the Big Island. "Violent behavior is something that is learned."

Joe said his abusive, negative behavior — he complained a lot, was domineering, confrontational, lacked compassion — stemmed from a fear of losing control and a sense of insecurity and inadequacy.

"I would use my temper tantrums and tyrannical episodes of exploding anger to demand respect," Joe wrote in response to an Advertiser questionnaire. "Much to my (dismay), this choice of behavior ironically only served to drastically lower the respect of my wife and children."

Joe, who has a graduate-school education and earns a six-figure income in a profession he wouldn't identify, didn't realize he was gradually destroying his family.

"The truly sad part of this sordid story is that I didn't listen to my wife when she warned me of the (consequences) of my actions," he wrote. "She said time and time again that she was tired of my being a boiling cauldron of angry water that spilled out and scalded her and the children."

The couple eventually divorced, and Joe's ex-wife and their two children moved to the Mainland. "I paid a huge price," he said. "I've lost everything that's most important to me."

Hundreds of domestic abusers go through intervention programs in Hawai'i annually, though the totals have declined in recent years as convictions have decreased. Over the past decade, for instance, the number of batterers who have taken intervention courses at Family Peace Center, one of two main providers of court-mandated programs on O'ahu, has dropped to 300 to 400 annually, from about 500 to 700.

One of the chief aims of such programs is to change the behavior of offenders.

Whether the programs succeed on a long-term basis is difficult to gauge — here and nationally — because of a lack of data.

The nonprofit agencies that typically run the programs barely have enough money to maintain existing services, let alone fund the collection and analysis of data showing how offenders behave long after completing the courses, experts say.

"We are so data-poor in this state," said Charlene Baker, a University of Hawai'i assistant professor who has done extensive research in the domestic violence field. "We don't know whether what we're doing is working."

On a short-term basis, the agencies here say their data indicate that the programs generally result in improved behaviors, especially during the roughly six to seven months offenders are taking the weekly courses.

Kata Issari, program director for the peace center, said staff assessments consistently show that at least 95 percent of offenders who complete the center's program show improvements.

Torres said his Big Island course typically achieves at least a 70 percent success rate.

But once the abusers complete the programs, the behavioral information that is collected is much more limited. Does the abuser revert to his old ways a year later? Two years later? Those questions are much harder to answer.

Torres said the offenders nonetheless tell him the program does make a difference.

"One of the most common responses I get from the men is, 'Why isn't something like this taught to us at a younger age? Why isn't something like this taught in high school?' " Torres said.