Jealous alcoholic Carl Mills, 28, bombarded his partner with threatening texts and, convinced she was inside with another man, warned: "I will burn your house down."
Mills stood unemotional and apparently uninterested as the jury at Newport Crown Court delivered three unanimous guilty verdicts.
He then sat and listened to a family victim impact statement read out to the court by prosecutor Gregory Bull QC.
More top news
Former Liverpool striker Djibril Cisse has been arrested as part of an investigation into a blackmail case
Shadow Chancellor John McDonnell has come under huge pressure from party MPs after he made a major economic u-turn.
Two orphaned sisters separated in South Korea have been reunited after being hired at the same hospital in Florida.