The jury found Allan Rush guilty of second degree murder after more than five hours of deliberation.
Rush was also found guilty of sexual battery.
The prosecution says Rush was having a hard time dealing with his breakup with Sarah Fields and killed her during rough sex.
Fields’ family was overcome with emotion as the judge read the verdict in court.
Christina Fields, the victim's sister, said, "It's kind of a sense of closure for me, but it’s also a new and better beginning to something that I don't have to think about. All I can think about now is worrying about how Sarah lived instead of how she died all the time."
Jack Campbell, prosecutor, said, "I'm pleased that the jury was able to sort through these facts and recognize that this was a murder. I'm happy that the jury was able to find indeed that Sarah Fields didn't deserve to die this way."
Rush was led out of the courtroom in chains soon after the verdict was read.
Lawyers from both sides expect to be back in court on November 29 for a hearing to determine when Rush will be sentenced.
He now faces life in prison.