The other honeymoon is over.
In March, the honeymoon between the new Coalition Government and the public ended after the mishandling of Labour's summer school complaints and the bumbling around New Zealand's position on Russia.
September marks the end of another honeymoon - between the partners in the Coalition Government, Labour and New Zealand First.
This week also marks another milestone: Peters finally came clean about how he sees his party's status in the relationship, as an equal partner to Jacinda Ardern's Labour which explains a lot.
This week has been more like the first falling-out rather than a crisis in the relationship but both parties behaved very badly to the other.
Firstly, New Zealand First behaving badly: New Zealand First's attitude to the Employment Relations Amendment Bill – expressing no support for it having supported it at Cabinet - verges on bad faith and not surprisingly angered Labour.
The bill is hugely important to Labour, being the first set of workplace reforms to reinstate measures conducive to collective bargaining.
New Zealand First extracted a major concession before it started its parliamentary journey in the dilution of Labour's bid to get rid of the 90-day trial.
New Zealand First's refusal to express support for the bill this week is part of its way to try to squeeze out more major concessions along the way for regional employers.
Imagine the upset if the tables were turned on a bill that was important to New Zealand First, say the party-hopping bill, and Labour kept withholding its support until more concessions were extracted along the way.
It took Peters four days to say that the bill would be passed, which is his roundabout way of saying that even if New Zealand First does not get what it wants, it will still vote for it.
Coalition partners behaving properly don't conduct themselves like that. Basic Coalition etiquette is missing.
What this week has shown is that neither party truly understands the other. Theirs is a political marriage of expediency, not compatibility.
Ardern will be using a major speech on Sunday to try to draw a line under the recent untidiness but Labour is not without sin in that regard either – as became glaringly obvious on Monday.
Anybody who has studied Peters, and surely someone in Labour has, should know he would baulk at a formal extension of the "partnership" between Maori and the Crown, which is being embraced by Ardern.
The plan for an agency to oversee the thousands of Crown commitments in Treaty of Waitangi settlements was not the problem. It is a sensible response to a contractually complex state of affairs.
The problem is its less defined role in promoting and supporting new directions for the "partnership" between the Crown and Maori and where that might lead.
Alarm bells should have sounded when Crown-Maori Relations Minister Kelvin Davis held supposedly public hui on marae up and down the country to which anyone was welcome except the media. These closed-door public meetings were held in order to design his portfolio.
What was supposed to be a piece of historic symbolism turned into an awkward shemozzle.
The answer was supposed to be unveiled on Monday at a partnership ceremony with Titewhai Harawira in the Cabinet room after it had been rubber-stamped by Cabinet, but New Zealand First vetoed it, and not unreasonably in the circumstances.
What was supposed to be a piece of historic symbolism turned into an awkward shemozzle at which no New Zealand First ministers were present.
Whatever consultation had been done with New Zealand First, it was not sufficient. No one had bothered to see the incompatibility between Labour's partnership utopia and Winston Peters' views on the Treaty and partnership – long held views but expressed in a speech just 18 months ago.
In it he said the term "partnership" – a principle proclaimed by Lord Robin Cooke in the Court of Appeal 1987 –was "an unfortunate term that has created legal chaos with activist judges, bureaucratic meddlers, Treaty lawyers and 'Treaty industry' taking advantage of the void it opened".
"It has created an insidious culture of division and parallel systems which we grapple with today."
In the non-stop negotiation that goes on in the Coalition over matters arising, there are plenty of issues that won't need Peters' explicit sign-off. But not to recognise the significance of this issue was a failure.
The most controversial elements of the Crown-Maori partnership is the implicit concept of being equal partners – which is apposite given Peters' tantrums this week over the "Labour-led Coalition".
Ever since MMP began in 1996 with the fateful coalition between New Zealand First and National, it has been accepted practice by politicians and media to describe a Government as National-led or Labour-led Government depending on the largest party.
It is not a pejorative term, at least it wasn't until this week. But Peters this week has decided it is an offensive term and refused to answer questions in Parliament because Paula Bennett described it as Labour-led.
When Bennett used the term "Winston-Peters-led Government," Speaker Trevor Mallard took two questions off National as a penalty.*
Yes, New Zealand First has veto power in a Coalition in which decision-making must necessarily be by consensus. Decision-making by votes would amount to a break down in the relationship. But actually it is still a Labour-led Government. That is a fact.
Peters appears to have no ability to stand back and see how his belligerence and petulance reflects badly on the Coalition.
That inability to take responsibility for his own failings was on display this week in an interview on Newstalk ZB when he – veteran politician of nearly 40 years - blamed a Newshub reporter for the Coalition shambles over its refugee policy two weeks ago. His insults were a bullying attack on a relatively junior reporter.
Her "crime" was to have asked if it was Government policy to double the refugee quota.
It would not have been hard for Peters at the time, or now, to say that that was Labour policy and that Cabinet has not reached a decision yet on refugee quotas.
Instead of blaming others, it is time for him and Ardern to address their own failings in the relationship.
*An earlier version of this story incorrectly said Speaker Trevor Mallard had taken two questions off National for Bennett repeating the term "Labour-led."