Her body was found with a knife still stuck in her neck. She had been stabbed 38 times and last year a Wellington jury found Preston guilty.
He was sentenced to a minimum 19 years for murder and breaching a protection order.
Preston maintains his innocence and has filed an appeal against both his conviction and sentence in the Court of Appeal.
Mr Hoyhtya, who has described Preston as "evil" and "the beast from the Bible himself", moved to New Zealand after her death.
He and Ms Fan planned on spending their lives together here but Mr Hoyhtya has decided there's nothing worth staying for, especially Preston's appeal.
A hearing date is yet to be set but whenever it is, Mr Hoyhtya has no interest.
"It's just a waste of taxpayer money," he said today.
"It's just madness. It's wasting everybody's time and money."
Instead, Mr Hoyhtya's putting his house on the market and selling his car, trying to get Preston out of his mind.
"I don't waste my energy on this guy anymore."
After he's sold up, Mr Hoyhtya might even have a hunting holiday in the South Island.
He knows he doesn't want to stay, however, saying after Preston's sentencing he only had his work left for him in New Zealand.
"This country holds nothing for me because I don't have the woman I love. That was the primary reason I wanted to come here. I've not been happy here."
Preston, 60, was described by police as a strong suspect "from the word go".
Ms Fan was 37.
