Shane Jones' partner, Dot Pumipi, says the MP's greatest fear in making the decision to resign was that his phone would stop ringing and he would get withdrawal symptoms from the sudden lack of attention.
Ms Pumipi said Mr Jones had pondered some time before making his decision.
"In the last couple of weeks with the decision he's been making he has had 'withdrawals', and that is purely because of the fear his phone will stop ringing. He was worried he would wake in the middle of the night and feel that withdrawal. He's so used to his phone ringing, he's that kind of person, and all of a sudden that's going to stop. When it comes to the end of Parliament it's going to be tough and he's going to feel a bit lonely, I think."
However, she said as soon as he made his decision he was happy with it. The final decision was made on Sunday night after Mr Jones talked to Ms Pumipi and then his father.
She had told him he had nothing to lose.
Asked whether she was to Mr Jones' career what Yoko Ono was to John Lennon's, she laughed and said she had told him she'd support him whatever he did.
"I said to him 'whatever you do, you must make this decision for yourself and you must take responsibility for it yourself'."
She said Mr Jones had been on a high since the leadership campaign last September.
"Shane never expected to get through, but he definitely gave them a run for their money on the contest.
"He would have been the perfect Prime Minister."
Ms Pumipi said Mr Jones' father was also a key person.
"His father said it was time, he had been on a high in Parliament and if he had been given an opportunity in another role, he said 'do it now. You'll have disappointed colleagues and some disappointed voters but they will get over it."'
She said Mr Jones also felt some responsibility to Maoridom, especially in Northland where Mr Jones is Labour's only Maori MP.
She said there was a further upside to his decision: "I can go back to Countdown."
Mr Jones' campaign against Countdown has been handed over to Labour MP Clayton Cosgrove.