The erratic work hours.

The stories that just don't quite add up.

Infidelity expert Ruth Houston, author of Is He Cheating on You? - 829 Telltale Signs, says, "You run the risk of falsely accusing your partner of cheating if you reach this conclusion on the basis of just a few telltale signs. A person who's really cheating will display dozens, possibly even hundreds, of infidelity signs." She says all you have to do is look. "Where there's one sign, there are dozens of other corroborating signs just waiting to be found."

Alcoholics and cheaters have lots and lots of warning signs in common. Why? A super-sized ego means that both regularly put their own needs above everyone else's.  Doug Thorburn, author of How to Spot Hidden Alcoholics (www.galtpublishing.com) suggests that due to an inflated ego, a huge number of alcoholics cheat, and that by looking for early warning signs of alcoholism, you can also avoid those with a strong potential for cheating.

Whether the cheater is a man or a woman, the signs are the same.  Are you dating a heartbreak-waiting-to-happen?

Moving Truck Mike 

Forget about the victims of the new corporate culture of "You Gotta Move On to Move Up."  If your guy willingly changes apartments as often as he changes his clothes, he's probably running away from something. Could be bill collectors, could be the ghosts of relationships past, but most likely it's himself. Thorburn says early-stage alcoholics move frequently as well. "This may be to switch identities, in a sense, since they have often ruined the lives of others, or to inflate their egos with an additional dose of stress and excitement in their lives."  This is a sign of someone who jumps to the next hot thing rather than staying where he is and trying to make things better. A volume discount at U-Haul can only be a bad sign.

Telephonitis Theresa

You know the type. You see them in their cars, at restaurants, in the aisle at Wal-Mart shouting the details of their recent gallbladder surgery into a cell phone. According to Hidden Alcoholics author Thorburn, "Telephonitis" is when someone attempts to control others "by attempting to force them to talk during all hours of the day or night." Another big clue? Trying to control someone by hanging up on them. According to Thorburn, "This is a variation of intimidation and evokes a high sense of self-importance," especially when the phone slammer initiates the call herself. Watch for other cell phone clues as well. Marriage therapist Wendy Allen (www.survive-the-affair.com) says, "Almost everyone who cheats has a cell phone for "private" calls. Find and check those cell phone records for a strange phone number that is listed repeatedly." Another warning sign? Odd phone numbers found on pockets, written on receipts or other little scraps of paper.

Brokeback Bob

Who doesn't love a romantic cowboy movie?  The Brokeback Wives, that's who.  Infidelity expert Houston says, "According to the Centers for Disease Control, more than three million women are, or have been, wives or girlfriends of men who secretly have sex with other men." What's more, she says, is that "according to the Family Pride Coalition, 20 percent of all gay men in America are in heterosexual marriages." Just because he spends loads of time with a member of the same sex doesn't mean he's not cheating. It doesn't mean he is, either. Just know that same-sex cheating is cheating just the same.

Reckless Ralph

He drives like a lunatic, honks at old ladies who don't have the good sense to go 80 on the freeway, and sees the shoulder as his own personal expressway during rush hour.  Thorburn says, "Watch out for reckless drivers, a classic example of 'I'm important, and others don't matter.'"

"It's Not Me, It's You" Sue 

Her boyfriend is too jealous, her boss is too stupid, and the rest of the planet just doesn't get it. According to Thorburn, if your date sees everything from a "self-favoring lens" (known as "Euphoric recall") she may actually believe she can do no wrong. If an It's Not Me, It's You" Sue violates the rules, Thorburn says, it is the rule, not her, that is wrong.  She may have cheated, but it's your fault.

Fashionista Frankie

Frequently when someone starts cheating they make changes to their appearance. Maybe your guy starts working out after six years of bliss on the couch. Maybe he has a sudden interest in Armani when nacho cheese-covered Chinos have always been just fine. From a new gym membership to new cologne, big appearance changes can mean big trouble.

Money-Laundering Matt

Affairs are expensive!  "Elizabeth Landers and Vicky Mainzer, authors of The Script: The 100% Absolutely Predictable Things Men Do When They Cheat say, to watch out when your guy has a lot of cash lying around, "expenses paid in cash are harder to trace -- no credit card statements and no cancelled checks."  Spending too little is a warning sign as well, Landers and Mainzer say, "He's gone to spending less because he can't be seen out and about." If you're living together or married, pay attention to the money. Frequently when someone is planning to leave, they start socking away as much as they can for themselves.

Nitpicking Nina

When someone is trying to end a relationship, they start picking nonsensical fights.  If you find yourself arguing over such pressing issues as the correct way the toilet paper roll should go, or why Hulk Hogan, not The Rock, should be crowned King of Wrestlemania, your partner is trying to make you look like the bad guy so she doesn't feel as bad when she leaves. 

"That's it!" she'll scream, after another paper versus plastic bout. "I can't take this anymore!  I'm LEAVING!"

Workaholic Wanda

She's working late all the time.  The big boss needs her to come in on Saturday (again) for yet another emergency presentation on the Smiley Sardine account. Allen says, "Work is a common excuse for absences. Drop by unannounced, more than once. Seventy per cent of affairs happen in the workplace."   

Frigid Fabio

Maybe your partner doesn't have much interest in sex anymore, or worse, he's got a new bunch of tricks and a shiny new cattle prod with the tags still on it.  A partner who has lost interest may be getting his or her needs met somewhere else, or he or she may be trying to separate from you emotionally. A dramatic change in sexual behavior usually means two things: he's either learning it somewhere else, or he's getting it somewhere else.

So what should you do if you suspect your partner is cheating?  Throw his clothes out on the lawn?  Quit your job and trail her like you're trying out for a cameo on Law & Order?

Houston says, "Never ask a cheater if he's cheating -- the answer is always 'no.'" She recommends that you, "don't give any indication that you suspect anything at all."  The best strategy is to collect all the information you can, and write everything down, "even if it doesn't make sense at the time."

Houston suggests you then confront the cheater and let him or her know you have proof of the infidelity, allowing you to get right to the meat of the discussion: how did this happen, and what the cheater is planning to do now that you know, so that you can make an informed decision about what to do next. 

She says, "Speak up. Make it clear that cheating is unacceptable, and that there will be serious repercussions if it doesn't stop. The longer the cheating goes unchallenged, the less likely it is to stop -- and the stronger the bond becomes between the cheater and the Other Woman or Other Man."

But then again, maybe you're better off without them.