Sarah Doyle (32), from The Heath, Ramsgate, Gorey, had denied murdering Philip Doyle (33) in the course of an incident during the early hours of January 26, 2020.
Family members of the deceased shouted across the courtroom at Ms Doyle moments after she was acquitted, leading to gardaí forming a line separating Mr Doyle's family from her.
The week-long trial had heard Mr Doyle died shortly after receiving two stab wounds to his chest.
The jury began their deliberations on Friday and were told today that they could return a majority verdict.
The jury of seven women and five men returned their not guilty finding after just over six hours of deliberations.
Mr and Ms Doyle, originally from Bray, Co Wicklow, had married six months prior to the incident and had two toddler sons together, while Mr Doyle also had a daughter.
Patrick Gageby SC, for Ms Doyle, had earlier said there was a "history of abuse" in the relationship and that his client "producing a knife was a last resort".
Ms Doyle told gardaí that Mr Doyle had "dragged" her down the stairs by the hair when she returned home on the night of the incident and was "punched" by her husband.
One neighbour of the couple said he had seen Mr Doyle give his wife "a slap on the head" one day when he saw them arguing.
Another said she saw Ms Doyle with bruising on two separate occasions. One day she had a bruise on her arm and on another day she had a black eye.
Paul Green SC, prosecuting, said the couple had an argument which started upstairs and moved downstairs, before Ms Doyle obtained a knife and used it against her husband.
He said it was an unlawful killing that could not be justified on the basis of a proportionate use of force.
On the weekend of the incident, Mr Doyle's parents, Jackie and David, visited the couple's home outside Gorey.
Jackie and Sarah went out socialising in Gorey on Saturday but came home separately.
The jury heard that Jackie Doyle told her son "don't ask" when she returned, with phone calls and two texts following between Philip and Sarah Doyle. Two texts from Philip said "where the f*ck are you" and "if you wake any of the kids you'll be sleeping in the front garden".
Two of the neighbours said they heard Sarah Doyle shouting "self-defence" following Philip Doyle collapsing in the front garden of the house.
Gardaí took photographs of bruising to Sarah Doyle's nose and arm after she was detained.
In evidence from Assistant State Pathologist Dr Margaret Bolster, it was heard that the first strike was a "rapidly fatal wound" from a kitchen knife 19.5cm in length, causing a wound 16.5cm in depth.
It cut into the membranous sac around Philip Doyle's heart along with his right ventricle, causing his death as a result of hemorrhage, shock and blood filling the left lung, which also totally collapsed.
Sarah Doyle became emotional as the verdict was returned, as one of Philip Doyle's family shouted "are you serious" and others shouted at her.
Justice David Keane thanked the jury for their service in what he said was a particularly difficult trial and exempted them from jury service for 10 years.