The next month, he learned his girlfriend had also been dating another man since 2013.
She told police she wanted to end her relationship with him then but said he took it "poorly" and their communication "turned sour", according to court documents.
While she was in China, he made a Facebook profile to message her on and sent in total more than 700 texts, emails and messages.
Ashamed and humiliated, he concocted a plan.
She would come back to New Zealand to either be with him or break up with the other man so they could split with some "dignity". He also demanded she pay him the $300,000 he spent on her during their tryst.
Judge Claire Ryan said the man, who was struggling to make bank payments, spent everything on her - choosing a cheap car and clothes for himself instead.
"You gave her everything she needed and wanted - you even bought her a puppy."
He demanded that if she did not do one of his two options, he would release an intimate recording of her and gave her a deadline of March 10.
He told her he knew gang members in New Zealand and China who would pay her a visit.
Panicking and believing he would release the recording, she returned from China and the pair met on March 7 at Hotel Debrett in Auckland's CBD to discuss the deal.
He extended her deadline to March 14 but continued to demand she chose one of his options.
Unbeknown to him, she secretly recorded the whole exchange.
Armed with the recording, the woman went to the police who laid a charge of harassment, knowing it would cause the victim to fear for her safety. The man was arrested, fingerprinted and "dragged" through the justice system which Judge Ryan said brought him more shame. He admitted the charge.
A sensitive man of quiet nature and previous good character, the woman's betrayal became "overwhelming", she said.
As well, his property business was suffering under the pressure of the Auckland housing crisis and his adult twin children had cut ties.
The man's lawyer, Stephen Bonnar, QC, submitted evidence that the stress of being "cuckolded" caused the man to develop tics, anxiety, and gastro issues among other conditions.
The treats and messages were a result of the circumstances and not an anger management problem, though he'd since been to two therapy sessions, Bonnar told the court.
He asked Judge Ryan for a discharge without conviction and for permanent name suppression because the shame of a conviction would cause undue hardship on his mental and physical state.
The man was also required to travel to Australia and China and a conviction would affect that.
The judge declined both applications, saying while there would no doubt be further humiliation, trauma and embarrassment it didn't meet the "extremely high" threshold of extreme hardship for name suppression.
Judge Ryan, when declining the discharge without application, said the consequences of a conviction didn't outweigh the gravity of the offending.
She convicted and sentenced the man to nine months supervision and ordered him to undergo any recommended programmes, which she said would be healthy for him.
The man was granted interim name suppression while he considers whether to appeal the decision to allow his name to be published.
