If you're paranoid or afraid you're being cheated on, and you can't get past it, move on. Regardless of whether or not the person's actually cheating on you, you need to be able to trust the person you're with. If you can't trust said person, you're not in a good relationship for one reason or another.
Also, there are many psychological queues:
Check texts, from both sexes names. (The intelligent cheaters will give their 'on the side' a name that is unassuming. Examples: A guy's cheating with a girl named Desiree, but on their cell Desiree is listed as Ryan. A girl is cheating with a guy named Andrew, but on their cell the guy is listed as Lisa. The stupid ones, or the ones new at it will leave the names as normal.)
The different scents thing works on the unintelligent ones, but the smart ones buy a second set of everything for the other place they shower. But if you smell a perfume/cologne that you don't use on your significant other, that's a good sign. They can hide their own scent, but not the scent of the the other man/woman.
Someone listed a very good way regarding MSN/Facebook/other IM clients earlier in the thread. Another good indication is when they get snappy if you 'look over their shoulder' too much. AKA sit too close to them when they're on Facebook/MSN/texting etc. Everyone is entitled to their privacy, but being private to the point of paranoia indicates a cheater.
Also, there are many psychological queues:
Check texts, from both sexes names. (The intelligent cheaters will give their 'on the side' a name that is unassuming. Examples: A guy's cheating with a girl named Desiree, but on their cell Desiree is listed as Ryan. A girl is cheating with a guy named Andrew, but on their cell the guy is listed as Lisa. The stupid ones, or the ones new at it will leave the names as normal.)
The different scents thing works on the unintelligent ones, but the smart ones buy a second set of everything for the other place they shower. But if you smell a perfume/cologne that you don't use on your significant other, that's a good sign. They can hide their own scent, but not the scent of the the other man/woman.
Someone listed a very good way regarding MSN/Facebook/other IM clients earlier in the thread. Another good indication is when they get snappy if you 'look over their shoulder' too much. AKA sit too close to them when they're on Facebook/MSN/texting etc. Everyone is entitled to their privacy, but being private to the point of paranoia indicates a cheater.