While you may suspect your spouse of cheating, it may be challenging to actually prove it. Finding physical evidence was the successful method of uncovering deception in only 18 percent of cases, according to a survey titled "How People Really Detect Lies." However, this rose to 30 percent when combined with other methods, such as third-party information, the Michigan State University research showed.

Definite proof of cheating is difficult to come by, but a good first step is searching your spouse's possessions. Don't just look in the obvious places, such as his pockets or briefcase. You may find incriminating love letters in his car, or maybe even in the bin.

After you've searched the house, it's time to get online. Check her computer history to see if she's been on dating sites, and look at her emails and chat history to find suspicious messages. Don't forget the 'trash' bin, where there may be items your spouse deleted in an effort to hide them.

There are paper-trails that a cheating spouse leaves, which he will find it difficult to cover. Look at bank statements and phone records to see if there is anything out of the ordinary.

Searching her cell phone could unearth suspicious pictures. If a number you don't recognize shows up often, try searching for the number online, or calling it from another phone.

If you can catch your partner in the act, you may be able to elicit a confession of cheating. Most affairs occur in the workplace (ref 2, pg. 19), so if he tells you he's working late, but you suspect he isn't, wait outside his office to see who he leaves with.

If you're certain there's something going on, follow your spouse when she's meeting up with friends. In her book, "Surviving Infidelity," family therapist, Rona B. Subotnik says that you should be suspicious of your other half spending too much time with a friend.

If you've not yet managed to find definite proof, or you're worried about being seen tracking your spouse, you can always call in a private investigator to do your surveillance for you. Although the services of a PI are expensive, a professional has experience of catching cheaters, and will also know how to stay on the right side of the law.