In a "Nightline" exclusive, Jesse James claims that he was a victim of child abuse, and cited shame and lack of self-worth as factors that drove him to cheat on his Oscar-winning wife and destroy his fairy-tale marriage.
"I grew up with a huge amount of shame and fear and abandonment on my shoulders from a very young age and I think, you know, the way my mind rationalized [cheating], 'Well, you know, I might as well do whatever I can to like run her off cause she is going to find out what I am anyway and leave me anyway,'" James said.
The 41-year-old James said he cheated on Sandra Bullock, 45, with multiple women, but that it all stemmed from his own emotional shortcomings.
"The struggle within myself for the things that I did ...to damage marriage and my life and everything else, it's all me," James said. "I'm doing it because, you know, I've basically never felt good enough for anyone."
After multiple women came forward claiming to have slept with him and a paparazzi firestorm followed, James said he checked himself into rehab in late March to take refuge. Though James said he went in with "a little bit of an ego," the seemingly-tough owner of West Coast Choppers garage opened up and discovered what was at the root of his marital problems.
"After about two days I realized, 'Wow, I'm kind of more messed up than most of the people here.' It was like peeling an onion. Every day it was a new revelation about myself and the things I've been doing," he said. "I cried more in rehab in the last 30 days than I have in my whole life. No BS. That's the truth."
During his month-stint in rehab, James said he received treatment for sex addiction and anger management, but above all for being a victim of childhood abuse. Rehab, he said, forced him to confront memories he says he had for 30 years that he didn't realize had such an impact on him.
"Bike builder, 'Monster Garage' TV star, all that stuff is a huge smokescreen so that people won't see that I'm a scared, abused kid, a seven-year-old," James said.
James, a child of divorce, was raised by his father -- a man he claims was physically and emotionally abusive.
"He beat my ass pretty good a bunch of times...I just remember, like, clinched teeth, strained-neck look on his face," James said. "My whole childhood, I never had a chance to be a kid. ...I was always scared."
One incident stood out in James' mind, a time when he said his dad chased him in the dark.
"I tripped over this little low fence wire and snapped my wrist and I remember my dad laughed at me when I hit the ground and called me a dummy," James said.
"I was petrified of my dad ... It wasn't so much getting the sh** beat out of me or getting my arm broken or getting kicked or whatever or punched, it was the in-between time. It was the fear of that happening again," he said, getting emotional. "I was a terrorized kid and, I mean, it's really tough for me to think about now because ...Sunny is the age that I was when my dad broke my arm."
While he reflected on his memories of his father, James teared up and took a moment to collect himself.
In an email message to ABC News, James' father Larry James says the allegations of abuse are not true.
In rehab, James said he determined he wasn't a sex addict -- at least in the traditional sense.