Philip Polkinghorne is on trial at the High Court in Auckland, accused of murdering wife Pauline Hanna and staging her death as a suicide.
The defence argues Hanna ended her own life after struggling with depression for many years.
Detective Andrew Reeves continued giving evidence on Monday, telling the court the first communication police found between Polkinghorne and sex worker Madison Ashton was in 2015.
He said a document showed Polkinghorne made an $800 payment for a "one hour girlfriend experience" Ashton offered.
Reeves said Polkinghorne communicated regularly with Ashton in the days after his wife's death.
WhatsApp messages were sent between the pair after April 5 in 2021, the day Hanna died.
Reeves suggested Polkinghorne had deleted messages from his phone, but they were found on a phone belonging to Ashton.
However, Reeves told the court the messages were "scrambled", "unreadable", and "difficult to make sense of".
Police also recovered iMessages between Polkinghorne and Ashton starting from April 17 in 2021.
On that date, Ashton sent Polkinghorne attachments related to a plastic surgery procedure she was set to get done.
He said she would look "more than sensational" and "drive a tsunami of lust".
Ashton responded with a heart emoji.
On April 23, they sent messages to each other about their relationship, the court was told.
"If you passed away I wouldn't leave the house ever again," she said.
He replied: "Darling, you and I aren't going anywhere, we are going to last 100 years."
Ashton sent Polkinghorne a property for sale in New South Wales on April 25.
"Interesting, something to talk about," he replied.
Later messages showed them planning a vacation at a luxury lakeside lodge in Mount Cook.
In one, Ashton said 14 months was a long time to not be together in any relationship.
Polkinghorne replied that they would see how the trip went.
"There may be commonality or there may not," he said.
Ashton asked if he was breaking up with her.
"Sounds like you are breaking up with me what the f...?"
"F... no, Christ, never," he replied.
On April 28 in 2021 Polkinghrone told Ashton he wanted her to meet his sister, calling it "a big step".
Ashton's two phones were seized by police on August 30 that year while she was staying with Polkinghorne at the Mount Cook lodge.
