This story originally aired on October 26th, 2006
In a tree-lined neighborhood in upstate New York, Susan, 47, a mother of three, never imagined her life would spin out of control.
But she found herself in a marriage that escalated from controlling to violent -- as she says she became a victim of domestic violence.
According to the Centers for Disease Control and Prevention, approximately 5.3 million incidents of intimate partner violence occur each year in the United States.
But Susan's case is unique because her abuse was documented in a disturbing 51-minute home videotape.
Four years ago, Susan's husband ordered their 13-year-old son to videotape his mother being verbally and physically assaulted.
The chilling tape took a look behind closed doors into the brutal reality of domestic violence.
Susan told her story for the first time to ABC News' Diane Sawyer.
Susan was just 18 when she first met and fell in love with Ulner, a 26-year-old man she saw on stage.
Ulner was a bass guitarist in a popular local band, while Susan had just finished her first year of college.
They started dating immediately. Eventually, they got married and started a family, with Susan working at a health-insurance company.
At first, Ulner was just controlling, not so different from her own father. But, the more she complied, the more he demanded.
"The controlling was absolutely there from the beginning. … Without me recognizing it," Susan said.
The physical abuse started more than 10 years into the marriage, when, according to Susan, she forgot an item at a nearby grocery store.
"He hurt me," Susan said. "He hurt me badly. I just couldn't believe it. It's like you're almost outside your body watching and saying, 'This can't be happening.'"
Susan said that Ulner cut her off from her father and her family for many years, leaving her isolated with no one to talk to, and completely under his control.
In 2002, the family started struggling financially, and Susan returned to work at a new job.
The only escape she had from her controlling and abusive home life was her new friend and boss, Lynne Jasper.
Jasper and Susan were friends and working mothers who bonded by sharing stories about their kids.
"I would have thought it was a rock-solid marriage," Jasper said.
Shortly thereafter, Jasper overheard several phone calls between Susan and Ulner, and said she was horrified to hear Susan refer to him as "master."
"'Yes, master. No, master.' You hear it the first couple of times, you think, 'Wow, what a sick individual,'" Jasper said. "After you got to hear the conversations and know her [Susan], [you learned] that her dedication wasn't out of love and friendship, it was more out of fear and control."
Jasper knew something was wrong and started collecting clues -- even taking notes in her datebook, recording behavioral changes and visible physical injuries, marks and bruises on Susan.
On May 6, 2003, she wrote, "Talk to Susan re: head" because of a visible wound on Susan's head.
Jasper asked Susan about her mark, and Susan said she had gotten the lump from a box she was pulling down in a closet, saying that it had hit her in the eye.
Jasper let it go for the moment, but still had her concerns.
The physical violence intensified between Susan and Ulner.