There comes a moment in every fledgling relationship – however promising – when the hot-cheeked joy starts to fade.
Pet names such as Bozzie Bear and Otter begin to lose their charm.
Peccadilloes – messiness, high passion, vaulting ambition and a disregard for money – once so endearing, suddenly start to become annoying.
And the challenges of co-habitation, of trying to blend two very different lives into one, begin to hit home.
Picking up some plonk? Boris is pictured at the till of a Tesco Express is Islington, near his former £3.75million five-bedroom family home, at 8pm on Wednesday – 24 hours before night of row
Rucksack on back, crumpled as ever, he was in a hurry and, according to a witness, Boris was looking 'certainly not statesmanlike' as he rushed in to browse the two-for-one wine offers
And just perhaps – if you're used to living in a five-storey £3.75million family home in Islington and hoping to be become prime minister in the next few weeks – you might ask yourself why you're cooped up in a two-bedroom flat in Camberwell with a girlfriend 24 years your junior who's keen on yoga, healthy eating and protecting the environment.
If their recent humdinger of a row is anything to go by, Boris Johnson and 31-year-old Carrie Symonds seem to be past the honeymoon period. Well past it given Carrie's cries of 'get off me... get out of my flat!' unhelpfully recorded by a neighbour in the early hours of Friday.
The row sounded nasty. Friends have been quick to deny they are on the verge of breaking up. Yet there are certainly signs that the carefully curated all-new, slim-fit, low-alcohol prime ministerial Boris is feeling the strain.
Last week, photographs of the inside of Boris's Toyota provided a study of utter chaos – empty food cartons, water bottles, crumpled clothes, plastic bags, children's books, crumbs and receipts.
Johnson is currently cooped up in a two-bedroom flat in Camberwell with a girlfriend Carrie Symonds, 24 years his junior who's keen on yoga, healthy eating and protecting the environment
Carrie, pictured at the launch of Johnson's leadership bid. The couple have been receiving hate mail for weeks now and the entire vicinity of her flat is plastered with anti-Boris posters. They're even stuck to his Toyota's windscreen – nestling amongst the unpaid parking tickets
On Wednesday, he was spotted in a Tesco Express in Islington, close to his former marital home. Rucksack on back, crumpled as ever, he was in a hurry and, according to a witness, looking 'certainly not statesmanlike' as he rushed in to browse the two-for-one wine offers.
Two days later, he turned up at the Conservative hustings in Birmingham with one brightly patterned sock inside out and uncomfortably bunched, displaying a big chunk of pink ankle.
Perhaps all this is a result of the pressure he and Carrie have been under. They've been receiving hate mail for weeks now and the entire vicinity of her flat is plastered with anti-Boris posters. They're even stuck to his Toyota's windscreen – nestling amongst the unpaid parking tickets.
It's said that tensions have been growing between Boris and Conservative election guru Lynton Crosby over the fact that Carrie is becoming too involved in his campaign. Political insiders say she is keen to adopt a serious role behind the scenes, and is just as keen on No 10 as he is (pictured leaving Carrie's flat in south London)
Such a public meltdown must be excruciating for Carrie, a PR professional, who has spent months letting it be known via 'friends' how in love the couple are.
On top of all this, it's said that tensions have been growing between Boris and Conservative election guru Lynton Crosby over the fact that Carrie is becoming too involved in his campaign.
Political insiders say she is keen to adopt a serious role behind the scenes, and is just as keen on No 10 as he is.
There are growing concerns that her ambitions may be complicating his campaign. These are trials the couple have tried to face head-on, and together.
In April his eldest daughter, Lara Lettice Johnson-Wheeler, a journalist just five years younger than Carrie, wrote on Instagram that the past 12 months had been the 'hardest and most hurtful year of my life'. Last year, after details emerged that he had cheated on wife Marina Wheeler with Carrie, Lara reportedly told friends at a party that her father was a 'selfish b*****d'. Until this week he has been shacked up with Carrie in her south London home (pictured)
More difficult to weather together has been the fact that Boris is reportedly 'devastated' that his four older children, furious at his latest relationship, have ostracised both him and Carrie and have refused to even meet his girlfriend.
In April his eldest daughter, Lara Lettice Johnson-Wheeler, a journalist just five years younger than Carrie, wrote on Instagram that the past 12 months had been the 'hardest and most hurtful year of my life'. Last year, after details emerged that he had cheated on wife Marina Wheeler with Carrie, Lara reportedly told friends at a party that her father was a 'selfish b*****d'.
There have been persistent rumours that Boris, despite his well-documented infatuation with Carrie, privately regrets the end of his marriage to Marina – his extraordinarily long-suffering second wife, and mother to those four older children.
There have been persistent rumours that Boris, despite his well-documented infatuation with Carrie, (pictured together in March) privately regrets the end of his marriage to Marina – his extraordinarily long-suffering second wife, and mother to those four older children
Marina was happy to let Boris shine, to let him be 'front of house' as she busied herself in the shadows, paying the bills, sorting out the mortgage, raising their children, all while working full-time as a very successful barrister. She was calm while he was explosive. Carrie, of course, is not like Marina. As well as being dramatically younger, she is also volatile. Like Boris,
