He was stabbed to death outside their apartment building on Alma Street, off Waterloo in March of 2010.
Mr. Justice William Grant says the jury will have to decide if MacKenzie was acting in self defense or trying to settle a score out of anger. The jurors will have to determine her state of mind after a night of heavy drinking and history of violence in their relationship.
The judge has told the jury there was evidence Thomas assaulted her five different times on the night of the stabbing but did she have a safe means of escape which would include calling police.
The jury has also been told it can find her guilty of manslaughter if it believes she was provoked and lost control.
