It’s every woman’s worst relationship fear — that her man is cheating. We’ve all heard the statistic: half of all men cheat. And some experts say that number is even closer to three quarters. Could it be happening to you? Aside from finding lipstick on his collar, a mysterious condom in his pocket or, yes, a phone number on a napkin (helpful hints but unlikely clichés!), there are some red flags to watch out for to tip you off that something fishy might be going on. The following are six signs that should raise your eyebrows:

1. He’s Acting Differently.
The most telltale sign of a cheating man is that he’s acting differently than the way he used to. If any of the signals below describe your guy’s usual actions, don’t freak out and immediately assume he’s having an affair; he’s probably just being his quirky self. What you should be suspicious of is new developments, says Barbara Feld, LCSW, a couple’s therapist at Park Avenue Relationship Consultants in New York City. She says you should ask yourself, “Is what’s happening different than normal? Is he showing a real change in behavior?” If he’s always been private, hasn’t ever had the highest sex drive, or often flakes out on plans, that’s just who he is. It’s when he starts to be that way and never was before that you should start asking questions. 

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2. He’s Avoiding You.
If your guy has suddenly started coming home much later, seems to be making excuses to be out of the house, starts going away without you on the weekends, or just generally seems to be avoiding you, that’s a clear indication of trouble in your relationship. M. Gary Neuman, a licensed family counselor and the author of The Truth About Cheating, found that 61 percent of cheating men said they started spending more time away from home. Fifty-five percent of men about to cheat said the same thing. No matter how busy your guy may be, he should be making an effort to see you (because, hello – he loves you, right?). If he’s stopped making time for you, it’s not at all unreasonable to wonder if he’s making time for someone else. 

3. You’re Having Less/Different Sex.
You might think that cheating men stop sleeping with their partners completely. But that’s not always the case. According to M. Gary Neuman, a little less than half of cheating men report having less sex with their partner. Others keep having sex so that they don’t raise suspicions – sneaky bastards. So be alert to the amount of sex you’re having, but most of all, pay attention to the quality of the sex. Therapist Barbara Feld says sometimes when a guy is having an affair, the quantity of sex remains the same, but it’s the sex itself that changes. Maybe it used to be very romantic, and feel more like making love, and now it just feels like plain old sex.

4. His General Response to You Has Changed.
If a guy is having an affair, he may stop acting like the sweet, romantic man you fell in love with. Maybe he used to be very loving and kind towards you, but now he seems to get annoyed easily, be critical, or pick fights. If he’s consistently not being affectionate with you, don’t brush it off. Try to figure out why he’s different – and what could be distracting him, or making him feel guilty.