BBC
"Adam Vaitilingam QC, defending, told the court there was psychological bullying in their relationship.
He said: "There was an intellectual imbalance which resulted on Mr Keene being belittled by the deceased.
"We would say this was a period of low-level emotional abuse; it went on for considerable periods. This culminated in the threat to take away a child.
"You saw the text messages passed between them; he was trying to be pleasant and her sending him pretty vile texts in response. This all led to that fatal moment."
The judge said that he accepted the threat to take away the daughter, and the cumulative effect of emotional abuse by Gaby over a significant period, caused Keene to lose control.
After the passing of the sentence, the family of Gaby said there was "no right or wrong" in the decision taken.
A statement said: "We must respect what the justice system has ordered because at the end of the day, each one of us will have to live with the consequences of our own actions."