The most commonly asked question about celebrity culture is probably the easiest to answer. "What is the point," everyone loves to despair, "of all these ridiculous people?" But isn't it obvious? To make us feel so much better about our own dysfunctional relationships, of course.

Whitney Houston's daughter Bobbi Kristina Brown became the star of her own reality show, The Houstons: On Our Own, within months of losing her mother – but that looked like a positively good idea compared with the one she announced in the first trailer. The 19-year-old, we discovered, was getting engaged – to her adopted brother! Surprise! The Houstons weren't thrilled, but that didn't stop the cameras rolling. "No one knew that from a godson you would turn into a boyfriend. No one knew that," her uncle scolded the groom-to-be, as if a bit of warning would have made all the difference.

The only thing more upsetting than Rihanna getting back with Chris Brown was the fact that he didn't even have the good grace to look grateful. Having beaten the living daylights out of her in 2009, the rapper thought it would be a good idea to get a tattoo on his neck depicting a woman's bruised and battered face. To make matters worse, it was far from clear he had stopped seeing another of his exes.

For impenetrable complexity, however, their love triangle had nothing on the love pentagon stretching all the way from Washington DC to Kabul. General Petraeus was forced to resign as director of the CIA after his affair with Paula Broadwell, his biographer, was discovered by FBI agents when they identified her as the source of anonymous emails warning a glamorous military liaison officer, Jill Kelley, to keep her hands off Petraeus. Then it turned out that one of the FBI agents had been emailing Kelley topless photos of himself, but her inbox was already filled with thousands of emails from the head of US military command in Afghanistan considered so "inappropriate" that his nomination as supreme Nato commander was suspended.

If only they'd all been French, the generals would almost certainly still be in their posts. This year we learned that first lady Valérie Trierweiler had been simultaneously conducting an affair with a senior rightwing minister when she began her affair with the now president François Hollande. At the time she was still on her second marriage, while Hollande was living with the senior leftwing politician and mother of his four children, Ségolène Royal.

French politicians are not used to finding their intimacies splashed all over the papers, and when all this came out the first lady threatened to sue. But instead of keeping her head down, she then promptly took to Twitter to urge voters to vote for Royal's election rival – since when none of Hollande's children has spoken to her.

But who needs Relate when you've got a red carpet? Kristen Stewart and Robert Pattinson parted company when her affair with director Rupert Sanders hit the headlines, but no amount of private pain could stand in the way of the Twilight franchise juggernaut, and so the couple duly kissed and made up under the glare of a thousand flash bulbs, the first recorded instance of a celebrity couple mistaking a Hollywood press junket for couple counselling.

Simon Cowell is probably still wishing he'd been more discreet around his unofficial biographer, Tom Bower, who duly told the world about the svengali's secret affair with Dannii Minogue. Cowell's fellow former X Factor judge was decidedly unimpressed. He is unlikely to have made matters better by telling Bower, "I'm attracted to crazy women. I encourage crazy behaviour and I make them crazy… Every girl wants to be number one and they're very territorial." Unsurprisingly, Cowell ends the year single once again.

See also in relationships

• Starting too young: Harry Styles.

• The Kate-Ben-Jay Electronica Twitter storm.

• Vicky Pryce and Chris Huhne facing each other in court.