Judge Cooper described the text messages as a determined effort by Guise to stop his ex-partner giving evidence against him. Guise also assaulted his ex-partner.
The court was told Guise had numerous previous convictions, including 10 for misuse of a telephone, three for threatening to kill and three for criminal harassment.
In the victim impact report the complainant spoke of being extremely frightened and having to leave where she was living, Judge Cooper said.
While awaiting sentencing this week, Guise sent letters to the complainant which were intercepted by her mother.
A probation officer described Guise's offending as "obsessive, bizarre and vindictive'' and Judge Cooper said he agreed with that. "You have no insight into your offending and you are totally self-absorbed.''