Despite four recent world championships shared between them, the relationship status between Red Bull and Renault is now beyond 'complicated'.
I've not seen a schism develop quite as publicly as this for years – in fact, the last constructor/engine supplier deal I can remember actually falling over was the pre-season split between Ligier and Alfa Romeo in 1987, as Rene Arnoux (rather conveniently for Fiat) slagged off the powerplant and Alfa pulled the plug.
It seems impossible to think that a modern-day relationship could actually degenerate to that point, but it's been amazing that it's got this far – even into trading personal insults this week.
In the cold light of day, Red Bull and Renault simply have to make this relationship work. Whether there's a subplot such as persuading Renault into buying Toro Rosso and becoming a works team again, or an exit strategy that forces Audi's hand into joining F1 – right now there's a whole load of dirty washing going on in public.
Here's how the 'Entente Cordiale' has been torn to pieces, like that scene from Anchorman where all the rival news crews wade into battle...
"Boy, that escalated quickly"
Things didn't seem so terrible in the early days of pre-season testing. The early company line from Red Bull was "at least it's better than last year" – referring to its painful start to 2014 when its car could barely complete three laps without catching fire.
But as the F1 testing shifted from Jerez to Barcelona, the mood darkened appreciably.
Team principal Christian Horner said of the Renault power unit: "It does have more power, but it is not evenly distributed. There is still a problem with driveability."
And then came Melbourne…
"I mean, that really got out of hand fast"
Daniil Kvyat failed to make the start due to a lack of oil pressure caused the gearbox to overheat, while Daniel Ricciardo finished a lapped sixth stuck behind Felipe Nasr's Sauber, after qualifying two seconds off the pace in seventh.
In the aftermath of the Australian GP, Horner went on the offensive: "The situation just isn't improving. The reliability is unacceptable. The performance is unacceptable. Renault, at this stage, appear to have made a retrograde step.
"There needs to be change at Renault. It can't continue like this. We're the end user and it's just frustrating that it's not where it needs to be at the moment."
Helmut Marko also waded in with critical comments, but it was Adrian's Newey's "no obvious light at the end of the tunnel" remark that really stung Renault.
"It's very frustrating that we've been pushed into a position where we've got an engine which is quite a long way behind with no obvious light at the end of the tunnel with all sorts of failings," Newey told the Telegraph.
And then Renault bit back…
"It jumped up a notch"
Monday's interview with Auto Hebdo, and subsequent Malaysian GP preview, Renault F1's managing director Cyril Abiteboul dealt a blow in return, suggesting the chassis performance was also a factor in Red Bull's slow start to 2015.
"Yes, it's difficult to have a partner who lies," Abiteboul he said when asked how hard it was to hear Newey declare that the only problem was the engine.
"Adrian is a charming man and an engineer without parallel, but he's spent his life criticising engine partners.
"He's too old to change his ways."
"It did, didn't it?"
And then, to add a further sense of surrealism to the feeling of "did that really just happen?" we had a tweet from Abiteboul this morning.
How random is that? And the FIA is never one to miss a trick, and must be applauded for its adept choice of senior team representatives in Friday's press conference…
Cyril Abiteboul (Renault), Matthew Carter (Lotus), Robert Fernley (Force India), Paul Hembery (Pirelli), Christian Horner (Red Bull), Franz Tost (Toro Rosso)
So, it's all eyes on Red Bull and Renault this weekend then. Well, it's more interesting than watching two silver cars disappearing into the distance, isn't it?
And, who knows, someone might throw a trident next...