"He called her a bitch and she got up and dumped the glass of water in his lap and walked out," Ross' friend, Penny Bentley remembered.
Another time, Ross suspected Nunn of cheating on her.
Ross "had his phone, his Blackberry, and was going through it...He wouldn't give her the password...so she threw (it) in the river," Bentley said.
The relationship reached the point of no return on Feb. 17, 2009 with what began as a small fight that soon escalated.
"She said something about she wanted to go out the next night and get some chicken wings and he said, 'Well, I'm not real sure,' so they got into an argument about it," Bentley said. "She told me he got up to leave and she ran downstairs and blocked the door."
Bentley said Ross told her that Nunn pushed and hit her and that she hit him too, cutting his face with her ring.
Ross filed an emergency protection order. Two weeks after the fight, a judge ruled that Nunn did hit Ross and granted a restraining order, requiring that Nunn have no contact with Ross for a year.
Within 48 hours of the ruling, Nunn tendered his resignation from the Department of Health and Family Services.
"Beshear could not afford to have an avowed abuser as the no. 2 man in the cabinet that oversaw child and spouse abuse," Forgy said. "What (Nunn) had achieved in coming back was now splattered in the road."
Bentley said Nunn snapped, indulging once again in alcohol and cheap sex. But it got worse: Nunn was also obsessed with revenge. He wanted to get even with Ross, whom he blamed for destroying his career by filing for an emergency protective order.
"To him, it was she ruined his life, and... somebody had to pay," Bentley said.
Police who later investigated Nunn said he tried to get back at his ex-fiancee first by showing his friends nude pictures he had taken of her. Then, Ross's friends said, Nunn began stalking her.
"She would be in her family room and he would be outside on her patio, looking in her window," Redgefield said.
Nunn's obsession ultimately turned fatal.
On Sept. 11, 2009, as Ross was leaving her apartment for work, she was shot dead. There were no eyewitnesses to the murder, but thanks to her protection order against Nunn, police had a suspect.
Nunn was apprehended the same day and later charged with Ross' murder. In a deal to avoid the death penalty -- a punishment required by the domestic violence law Nunn championed years ago -- Nunn pleaded guilty in exchange for a sentence of life without parole.
"He will have to wake up every morning and think about what he did to Amanda and her family and what he did to his family," said Ross' mother, Diana Ross.