The pair would meet at her home and at friends' homes and the relationship continued for about five months, until the girl's death on July 18 in Rotorua Hospital's Intensive Care Unit.
Throughout the relationship, Tiumalu insisted that they had unprotected sex, resulting in the girl undergoing at least one pregnancy test, the summary states.
The girl's family had welcomed him into their home. He had told them he was only 20 and also told the family he and the girl were not having sex.
In May his wife, Elina Eva Tiumalu, found out about the relationship. He sent a text message to the girl on July 16 calling it off. His wife began texting the girl, telling her she would get friends to beat her up if she didn't leave her husband alone.
She also texted the girl pretending to be her husband, warning her to stop texting or she (Tiumalu's wife) would kill her and to watch her back.
On July 17 the girl's family rushed her to Rotorua Hospital in a critical condition. The girl died in the early hours of the next morning.
Rotorua Coroner Dr Wallace Bain is yet to hold an inquest into the girl's death.
Elina Tiumalu was charged with intimidation and pleaded guilty to the charge on February 15. The 21-year-old received a nine-month deferred sentence by Judge James Wier in the Rotorua District Court.
Judge Phillip Cooper yesterday ordered Tiumalu to attend a restorative justice meeting with the girl's family, if they wished to have such a meeting.
The judge warned Tiumalu that jail was "a likely sentence".
Tiumalu was remanded on bail for a pre-sentence report and sentencing on June 25.
