A Wellington jury today watched a filmed interview in which Michael Preston described his estranged wife as a manipulative woman who did not know how to keep her legs shut.
Mr Preston is before the High Court in Wellington, accused of fatally stabbing Mei Fan in November 2013.
Police arrested Mr Preston the night Ms Fan's body was found, and charged him with breaching a protection order.
Initially, they didn't tell him she was dead - but when they did, he wailed and sobbed and said to the police she constantly said she was going to kill herself.
He continued to sob during the first part of the interview, at one stage leaning back with his head against the wall and his hands over his face, sobbing, "It's not right, it's not right".
Mr Preston sobbed again when he was asked if Ms Fan had any relatives in New Zealand, saying she had no one.
"She reckons she's strong, but she's not", he said.
"She thinks she's so independent, but she's just a pussycat. She should never have been alone."
Mr Preston said he'd separated from Ms Fan and brought their children back to New Zealand, but when he found out her uncle had put a contract out on her life, because she'd lost him money in a ponzi scheme, he felt sorry for her and asked her to come and join him and the children.
As the interview went on, Mr Preston calmed down, telling the interviewing officers he and Ms Fan had lived as husband and wife with their two children, until she moved out in October 2012.
In the middle of 2013, he had begun going to her house again until she went all crazy and started making death threats to him, he said.
Mr Preston said they had been sleeping together and he asked Ms Fan if she had told her boyfriend about that - the boyfriend was a Finnish man, whom she had met in China in 2011.
He also claimed she had been sleeping with another man, three weeks after her boyfriend had returned to his home in Vietnam.
Mr Preston also said he thought she'd been having an affair with a father of their childrens' schoolfriends.
Ms Fan was manipulative and played one guy off against another all the time, he said.
Earlier on Thursday, an old friend of Mr Preston's gave evidence.
Graham Bullman said the accused was "obsessed" about getting Ms Fan out of New Zealand.
He often met up with Mr Preston during 2013 and the conversation would invariably turn towards the problems his friend was having with his ex-wife, he said.
He said Mr Preston was convinced Mei Fan was in New Zealand illegally and said she had at least two different surnames and possibly two different dates of birth and he'd given that information to the authorities with a view to having her deported.
Mr Bullman described the relationship between Mr Preston and Ms Fan as toxic.