Is your guy hooking up at work?

Identify the Biggest Threat

You may think that blond bombshell at the front desk has Man Stealer written all over her face, but the chick you least expect could be the real danger to your relationship. "She could simply have some quality that plays to your man's weaknesses or boosts his ego," says Susan K. Perry, Ph.D., author of Loving in Flow: How the Happiest Couples Stay That Way. Translation: She may not necessarily be a gorgeous vixen. Some suspicious chicks: "Women working on long-term projects with him or who have cell phone or pager access to him during off-hours," says Gratch. "Also, pay attention when a coworker invites him to nonwork functions, especially if he goes without you." That being said, try not to be paranoid about every woman that crosses his path — just keep your eyes open. Once you have the enemy in your crosshairs, you don't need to attack. "If you are uncomfortable, rude, or possessive when you see her complimenting your man or laughing at an inside joke, she'll pick up on your insecurity," says Lusterman. One strategy she might use to screw you over is making comments to him like, "Aren't you annoyed that she checks up on you all the time?" Stay cool and confident, and she'll have no ammo to use against you.