If you ever feel that keeping tabs on the antics of your man is difficult, spare a thought for those unfortunate enough to be saddled with a celebrity paramour. Upstanding role models and objects of desire these gents may be, but that doesn't stop most of them breaking the rules of guyhood many times over.
Come the end of the year, there won't be a doghouse in the world big enough to house these bad boys. Without further ado, it's time to draw up a charter of conduct for celebrity and civilian alike to live by.
Thou shalt not lob the gob on your ex while your current fiancée looks on
Case in point: Simon Cowell
Only Cowell could get away with such a brazen move ... just. Cowell often has his exes in tow, often at the same time. Yet last month, the mogul was snapped pulling a rather brave move. As the cameras looked on, Cowell pulled his ex Jackie St Clair in for a lingering kiss while current fiancée Mezhgan Hussainy stood nearby.
To her credit, Hussainy didn't look the least bit perturbed by the embrace. Then again, she's had to suffer the ignominy of watching her intended make glad eyes at Cheryl Cole -- in front of a TV audience of millions -- for weeks on end.
Thou shalt not brag about what your lovers are like in bed
Case in point: John Mayer
To be fair, many girls wouldn't object to being described by a former lover as being 'sexual napalm' in bed. But for Jessica Simpson, her ex-boyfriend John Mayer's Twitter revelations were unwelcome.
In February last year, bigmouth Mayer told 'Playboy' magazine that Simpson was like a "drug" to him: "And drugs aren't good for you if you do lots of them... Yeah, that girl is like crack cocaine to me. Sexually it was crazy. That's all I'll say. It was like napalm, sexual napalm."
Simpson went on Oprah Winfrey's talk show to talk about the episode. Looking upset and shaken, she said: "I don't want people to know how I am in bed."
Days after the interview hit the newsstands, Mayer admitted that, on reflection, he'd behaved like an "a-hole". You don't say.
Thou shalt not look for two in the bush when you have one in the hand
Case in point: Shane Warne
Cricketer Shane Warne has always been a tad naughty. Yet Liz Hurley seemed rather surprised when he jeopardised their fledgling romance by texting another woman. According to reports, Warne doggedly pursued Australian businesswoman Adele Angeleri and bombarded her with more than 100 text messages. Naughty!
Thou shalt not post less-than-flattering pictures of your wife on Twitter
Case in point: Russell Brand
This is perhaps at best a yellow-card offence, but no doubt Russell Brand copped no end of flak after posting a pic of his wife Katy Perry on the social networking site.
Perry is rarely seen without her trademark liner 'n' lashes regalia, so no doubt an unflattering pic of her, seemingly taken first thing in the morning, was an ill-thought-out move.
Brand was quick to remove the pic from his page, no doubt at his wife's behest. But alas, not quick enough. See also: Ashton Kutcher, who deemed it appropriate to post Twitter pics of his wife Demi Moore doing the ironing.. in her underwear.
Thou shalt not have more beauty products than your missus
Case in point: Gavin Henson
Not one to hide his light under a bushel, Henson is rather open about just how vain he is. "I'm probably as vain as any normal guy," he said recently, before adding: "I only let people stand on my right when photos are taken so my best side gets a good viewing. I have to work out every day for rugby, so my bod's usually up to scratch."
Other reports hint that the rugby star and one-time partner of Charlotte Church is also fond of a wax-and-tan combo. He joked on the Jonathan Ross show: "It takes two hours to get ready -- hot bath, shave my legs and face, moisturise, put fake tan on and do my hair, which takes a bit of time.
"I need my fellow players to say I'm looking good, I need it for my confidence -- it gives you a boost." But you know what they say about anything that is said in jest ...
Thou shalt not invest more in your bromance than in your relationship
Case in point: George Clooney
It rarely bodes well for a girlfriend when the close friendship between Clooney and Brad Pitt is described as "George's longest-lasting affair". The two have starred in four films together and their bromance shows little sign of simmering down.
Clooney has played the love-in down in the past: "I don't even really like the guy," he joked. "He knocked me off of some of those 'People' Sexiest Man Alive issues, and there is no forgiveness."
In 2006, Brad took out full-page ads in 'Variety' and 'The Hollywood Reporter' congratulating George on nabbing the title -- by featuring a photo of George sporting a mullet from back in the day. So when George next went on a talk show, he brought along photos of Brad wearing too-skinny trousers and a green beret. Oh, you two ...
Thou shalt not forget your wife's birthday
Case in point: Bono
Upon the release of the Dublin-shot video for U2's 'The Sweetest Thing', a nation gushed collectively. Yet there was an intriguing tale behind Bono's grand gesture, as the song was written as an apology to wife Ali.
Said the singer at the time: "It was Ali's birthday and I didn't make it for the birthday. I wanted to write her a little sweet song, but it ended up a little bit sour, as all the best love songs are. I can't write these straight love songs. They make me want to throw up."
Not such a sugary, heart-on-sleeve romantic after all, then.
Thou shalt not deny we're together
Case in point: Angus Stone
The Australian folk singer is dating 'Transformers' beauty Isabel Lucas -- not that you'd know from his actions. After bringing the brunette along to the ARIA awards in Australia, Stone was reticent about the romance.
"We've known each other for a long time -- I guess we're together," he shrugged.
Here's hoping you're more effusive about the relationship behind closed doors, Angus.
Thou shalt not cry like a baby to the press after a break-up
Case in point: Alex Reid
Alex Reid was hardly a paragon of discretion during his year-long marriage to Katie Price, but even after the two split earlier this month, he refused to take the high road.
Upon seeing pictures of his ex-wife partying at a ski resort, Reid bleated to a tabloid newspaper, in between reported visits to a life coach: "I feel like one of those puppies brought into the house for Christmas and chucked into the streets a few weeks later. She had me when it suited her, and now she's changed her mind. I've been crying for a month.
"When I began to fear that Katie wanted to end our marriage I was absolutely devastated. I didn't want to split up with her. I love her. I clung on to the fact that it might not end.
"Like I say, Katie treated me like a dog, I feel like one of those unwanted ones. They say a dog isn't just for Christmas, don't they?"
Note: likening oneself to a dog is not the best way to get back into a girl's good graces.
Thou shalt not go off with your ex's best friend
Case in point: Richie Sambora
Bon Jovi guitarist Sambora holds the distinction for being a prong in one of Hollywood's most bizarre love triangles.
After divorcing his actress wife Heather Locklear, Sambora struck up a relationship with fellow actress Denise Richards in 2006.
So far, so unremarkable ... until it transpired that the two girls were BFFs. In fact, one Hollywood report insists that Denise was the friend who prompted Heather to split from her husband in the first place.
The Sambora/Richards relationship has since bitten the dust, yet the two women are still no longer on speaking terms.
But perhaps that goes without saying.