Zimmerman spoke in an interview with Katie Couric on her syndicated talk show "Katie," People magazine reported.
"I haven't seen him in a couple months, but it certainly seems like something snapped in his spirit," Zimmerman said.
George Zimmerman, who was acquitted in July of killing Trayvon Martin, 17, in Sanford, Fla., was released on bail Tuesday after being charged with pulling a gun on his girlfriend. He was ordered to stay away from guns.
"I certainly hope that there are no casualties. I hope that there's no violence, but he does seem like a ticking time bomb," she said. "I know I'm certainly afraid. I just hope that he can get maybe the help that he needs to deal with his situation and that no one else will be hurt."
Zimmerman told Couric she does not believe her husband deliberately killed Martin, an unarmed black teenager who was walking to a relative's house, the Orlando Sentinel reported. She said her husband is not a racist.
But she did seem to have doubts about her husband's actions that night.
While Zimmerman described her husband as "emotionally abusive" recently, she said he was not like that when they married in 2007.
"We were great friends, and I thought he was a wonderful person. That's why I married him," she said.
She also said she was "selfish" when she did not file charges after police responded to a domestic violence situation in which her husband allegedly threatened her and her father.