IT’S inevitable, really.

No matter how strictly you screen the shares, now that it’s halfway through the summer, the cracks are starting to show in your once-perfect group of Hamptons housemates.

Come mid-July, weekends are rife with moody silences, door slamming and dark mutterings about a wasted $4,000.

Don’t blame yourself – or your house manager, for that matter. After all, forcing a bunch of finicky New Yorkers with independent lifestyles, opinions and party habits to cohabit in even the most spacious of beach palaces is a recipe for disaster – or at the very least, a reality TV show.

So how can you make it to Labor Day without pulling a Lizzie?

Here, Pulse’s field guide to the six stereotypes who always seem to ruin it for everyone – and some tips on how to deal with ’em, from the experts.

THE SOCIALITE

Distinguishing features: Long blond straight hair by Frederik Fekkai (à la Lizzie)

Got in via: Daddy’s checkbook

Wears: Lulu Guinness shoes, L.L. Bean tote, Harry Winston diamonds on the beach

Catchphrase: “Noah’s put me on the guest list.”

Leisure activity: Surfing Friendster.com

Reads: The List in Hamptons magazine, “Trading Up” by Candace Bushnell

Listens to: Mark Ronson’s latest mix

Eats: Nothing

Drives: Mercedes CLK500 convertible

Next year: “I’ll be in Europe, sweetie.”

How to deal: “Shame her into silence by out-socialiting her: Make sure your phone rings twice as often as hers, you get three times as many dinner invitations and when she goes to Jet East, you go to Puffy’s”

– Jared Paul Stern, Nightcrawler

THE FRAT BOY DRUNK

Distinguishing features: Beer breath, bloodshot eyes, two days’ stubble

Got in via: Sent fake photo and resume to Craig’s List when Alexis dropped out

Wears: Un-ironic Metallica T-shirt, three-day-old tightie whities, socks – and nothing else

Catchphrase: “Who drank all my friggin’ beer?” (He did. He just can’t remember.)

Leisure activity: Jumping on your bed for some “roughhousing” at 3 a.m.

Reads: Side of beer can to establish alcoholic content

Listens to: Eminem

Eats: Leftovers

Drives: Under the influence

Next year: Twelve-stepping

How to deal: “Wait up until he rolls in drunk, whip out a video camera and film him making a fool of himself. Then make him watch it the next day. He’ll never drink again.”

– Anonymous alcoholic, Manhattan

THE OBSESSIVE-COMPULSIVE FREAK

Distinguishing features: Eau de Clorox

Got in via: Seemed like a good idea at the time to have one organized person in the house

Wears: Apron, rubber gloves, scowl, breathing mask

Catchphrase: “No, no, honestly, it’s fine, I like mopping.”

Leisure activity: Sweeping the sand off the deck

Reads: “How to be a Domestic Goddess” by Nigella Lawson

Listens to: The ordered strains of Bach

Eats: Anything in a no-mess carton

Drives: Ford Explorer SUV for carting cleaning materials from city and back

Next year: Back in the same house having driven everyone else out

How to deal: “Hide all the cleaning equipment.”

-Anonymous reformed obsessive-compulsive freak

THE LOTHARIO

Distinguishing features: Inability to pass mirror without checking appearance

Got in via: Sleeping with everyone

Wears: Lacoste polo shirt, mirrored shades, white jeans

Catchphrase: “Wouldn’t we be more comfortable back at mine?”

Leisure activity: Masturbation

Reads: “Mama Gena’s School of Womanly Arts”

Listens to: Barry White commemorative re-issue

Eats: Oysters

Drives: Ducatti 999

Next year: Scoping new pastures on the Jersey shore

How to deal: “Peer pressure. Gather everyone together and tell him that the fact that a new face appears at the breakfast table every morning harms the intimacy of the group.”

– Sex-addiction psychologist Stephen Reich, Manhattan

THE STILL-AT-WORK BUSINESSMAN

Distinguishing features: Chewed fingernails, furrowed brow

Got in via: Paying three times as much as everyone else

Wears: Vertu mobile phone

Catchphrase: “Can you hear me now?”

Leisure activity: Fiddling with his Blackberry

Reads: “Who Moved my Cheese?” by Spencer Johnson

Listens to: Bloomberg Radio

Eats: If he remembers to

Drives: Lexus GS300

Next year: Buying his own place

How to deal: “Ask him to conduct his business in the city, or at least his room. It’s best to think of a house share as a family, and he needs to be treated like a child to get him to behave.”

– Clinical psychologist Allison Edwards, Southampton

THE KITCHEN NAZI WHO CAN’T COOK

Distinguishing features: Magically appears in kitchen as soon as food prep is under way

Got in via: She’s a legacy – her ex-boyfriend used to run the house.

Wears: Comedy apron

Catchphrase: “How were you planning on cooking that?”

Leisure activity: Feeding her chili to the dog when no one’s looking

Reads: Martha Stewart Living, natch

Listens to: The Food Network

Eats: None of her own cooking

Drives: Everyone to the restaurant when she burns the baked ziti

Next year: At the Culinary Institute of America, paid for by her friends

How to deal: “Place a big plate of their nastiest food in front of her and make her eat it. If she won’t or can’t, then you say, ‘So why should we?’ You’ve got to be harsh.”

– “Big Brother 3” finalist Eric Ouellette