That's because many of the means that people use to catch a cheating spouse are actually illegal! Here are 3 methods that, while they may be great at catching an adulterous mate, won't hold up in court--and may even get you some jail time if you're found out!

1. Recording your spouse's phone conversations. You may think that a recorded phone conversation is all you need to rightfully confront your spouse. And this will in fact give you the moral certitude you need, to do whatever it is you feel needs to be done. But did you know that phone taps by private citizens are illegal?

This kind of thing won't hold up in a court of law. In fact, it could get you a fine--or even worse, a bit of jail time! And it's not going to look good if you go through divorce proceedings.

The only time it's legal to record someone's phone conversation is

A) When you have told them that you are recording the conversation (usually done for an interview)

B) When you are acting as an agent of the law, with an appropriate warrant.

2. Recording your spouse's online chat sessions. Most people abhor the idea of using software that will spy on someone by recording that person's every move online. Our attitudes can turn around very quickly, though, when we think we're being cheated on.

Keystroke loggers provide you with a record of every chat your spouse had or email they have written. You can download key logging software on the computer your spouse uses. There are also physical key logging devices that look inconspicuous (usually in the form of a cable) that you can install on a desktop.

While key logging devices and software are no more illegal than microphones and recording software, the same laws that govern telephone communications, generally govern electronic communications as well.

This gets sticky with key loggers. It's generally legal to install one on your own computer. But you can run afoul of various laws and privacy statutes with these devices as well.

If you have to get one, then get one. Just make sure you know the laws in your area.

3. Using a GPS tracking device on your spouse's car. In most states, it's actually legal to place a GPS tracking device on the car that your spouse drives--provided that your name is also on the title.

Even if you don't use GPS tracker records as evidence of adultery in court, it may lead you to somewhere that you or a private investigator can take incriminating photos or gather other evidence.

Still, you may live in a state where part ownership of the vehicle doesn't count as 100% legal permission for you to install the GPS. Check the laws in your state. Until you know exactly your legal rights and responsibilities, be very careful how you use a GPS tracker (if you use one at all).