John St. Angelo was convicted Thursday in the murder of Suzanne Parsons.
St. Angelo will serve life in prison for the stabbing death of Parsons.
In December of 2013, he went to her north Fort Worth real estate office and stabbed her about two dozen times and slashed her throat.
St. Angelo later held a woman hostage and then was involved in a standoff with police before he claims he shot himself in the face.
St. Angelo testified he first tried to prevent Parsons from committing suicide and then he stabbed her in self-defense when she came at him with a knife.
In closing arguments, the defense tried to illustrate to the jury that it was a crime of passion by acting out 23 stabs.
Following the sentencing, Parsons' family released a statement saying, "Today, justice was served and a stand was taken against domestic violence."