Extramarital infidelity can destroy a marriage. In fact, it has been the leading cause of divorce for quite some time. Even without "proof", the suspicion that your spouse may be having an extramarital affair can be heart wrenching. Because you know your spouse better than anybody else does -- you will know when your relationship is changing. Others may not be able to see it, but that is due to the fact that the changes oftentimes start out subtly.

If you suspect that your husband or wife may be having an extramarital affair, ask yourself the following questions:

- Has your spouse suddenly become distant?

- Does your spouse make excuses to be away from you?

- Has your spouse suddenly started taking on overtime?

- Has your spouse made plans that exclude your input or even involvement?

These are amongst the most common signs that your spouse may be having an extramarital affair. Now, these are far from the only telltale signs -- you may notice changes in daily routines, personal attitude, or in your spouse's lifestyle in general. Honestly, the best way to "know" when your spouse is cheating, even without proof, is by simply paying attention to what is going on in your marriage and with your spouse.

Computers can be a major problem for husbands and wives -- they offer a new, and largely anonymous, venue for their partners to converse with others. When you walk in the room and your spouse shuts down the computer suddenly, or tries to divert your attention from what they are doing -- this may indicate that your spouse is hiding something from you. Online dating sites, or "married but dating" suites have made it very easy to connect with other people in your local area or anywhere around the world.

One other sign that your spouse may be having an affair is their inability to keep track of their "stories" that they tell you. For instance -- ask your spouse what they are doing again, unexpectedly, as they are getting ready to leave. Ask them what they are planning on doing while you are gone -- you may be playing the part of the forgetful spouse, but those who are having an extramarital affair oftentimes will lose track of their lies at some point, and these lies can be indicative of a cheating partner.

Now, while these signs can indicate that your partner is having an extramarital affair, they are not concrete evidence that your spouse is involved in some form of extramarital infidelity. Before you confront your spouse, you should have solid evidence that there really is something going on, other than their suspicious behavior. After all, they are your partner, and a false accusation is not something that can be undone.

If you decide you need a professional investigator that's an expert in Internet infidelity investigations don't just choose the first PI you see in the phone book. Make sure the investigator has a good reputation and is recognized as an authority in this type of cutting edge persoanal investigations.