9 Signs That He Might Be Cheating On You

When you get suspicious that your significant other is cheating, be careful not to appear to be paranoid. You have to walk a fine line — you don't want to make false accusations. So, while I'm sharing this list of cheating red flags, I concede that it's a tricky situation. It's hard to be sure if someone's cheating, but protect yourself: Be vigilant, and pay attention to your mind and spirit within the relationship. But, at the same time, be careful not to let anxiety lead the way because unnecessary paranoia will just drive your lover away.
Here are some red flags that may signal that your significant other is cheating:  
Less Sex

Unless he's Superman, he can only have so much sex. So, if he's getting it from another source, you might notice. Whether it's another woman or a porn addiction — even if he's not cheating — a decrease in sex signals serious issues in the relationship.
Jumpy Cell Phone Habits

In a perfect world, we'd be open about sharing our correspondence with our significant others. Most of the time, we trust that we don't have to worry about who is texting or calling them. But, if you notice that he is getting protective and/or nervous when he gets calls or texts, it may be cause for alarm.
Gushing or Talking About Someone Suddenly

You know that exhilarating feeling you get when you meet someone new and exciting? You want to tell the world about him. One of my exes began talking about a guy a lot near the end of our relationship — he just always seemed to be at her social gatherings that I didn't happen to attend. Sure enough, after she dumped me, she began dating him.
Disconnect

Even though relationships ebb and flow naturally, if you're sensing that he's drawing away from you, then there may be someone else. Emotional disconnect should be investigated regardless of whether it's caused by cheating. There's a problem if he's not laughing or seeming as passionate as usual. It's hard to spread love/passion between two people, so the person who used to have it will feel it slipping away if it's being given to someone else.
He's Pulling Houdinis

If he's disappearing, traveling, or unavailable to the point where you are starting to wonder, then he could be cheating. Also, these times tend to take on a pattern because it's tough to synch up schedules, especially in secret.  
Friends Acting Strange

His friends will certainly remain loyal to him in most cases. They will not let you know what's going on, but they will definitely be racked with guilt, and their behavior may change slightly when they are around you while protecting his secret.
Caught in Other Lies About Other Things

If you catch him in a lie, your trust will naturally be damaged. Don't hold a grudge — forgiveness is a good thing. You can forgive, but don't forget. If he consistently breaches your trust, it's establishing a pattern of behavior that leads to cheating. Do yourself a favor: If he keeps lying, whether these lies are big or small, get out while you can and don't let him talk his way back in.
Been There, Done That

I always say: "Once a cheater, always a cheater." If he's done it before, he's definitely capable of doing it again. It has nothing to do with you, which is why you can't say that he cheated on his previous lover because she didn't keep him happy. Cheating is a self-serving act in which the cheater doesn't take his significant other into consideration. If someone is upfront with you that he's made mistakes in the past, maybe give them a chance — but make it a long probationary period before you let your guard down.
Your Gut Tells You So

Don't ignore your sixth sense. People are gifted at sensing when something doesn't feel right. Whether there are red flags in your relationship that are clueing you in or not, if something feels off, don't ignore this feeling. Usually that feeling is right, and something intangible may have led to you figuring it all out.

Do you have any red flags that you'd add to this list? Would you say that you're generally good at figuring cheaters out, or do you seem to find yourself getting cheated on often? What sorts of behaviors do you think are characteristic of someone who could be a cheater?
-- marieclaire