Finding out if your spouse is using the Internet to chat is fairly easy. Unless he has taken thorough measures to hide the activity from you, you can discover the websites he has visited with a few clicks of the mouse. Even if he is tech-savvy enough to hide the activity on his computer, you might still have reason to be suspicious if he is suddenly spending an unusual amount of time online, making excuses for the behaviour or otherwise acting as if he is hiding something.
Notice how and where your husband is using the Internet. Watch to see if he is retreating to a private room to use a computer. If he seems nervous when you approach him, or quickly turns off the monitor, he may be chatting with someone. Observe him to see if he frantically clicks his mouse when you enter the room. He may be navigating away from a website he does not want you to see.
Monitor whether your husband stays up using the computer after you have gone to bed. If he is doing this regularly, he may be chatting online. Watch for changes in his behaviour, including the computer becoming more important in his daily life than family relationships.
Click "History" on the Internet browser's menu, or press the "Ctrl," "Shift" and "H" buttons simultaneously. Scroll through the websites he has been visiting. If you are not familiar with the name of the website, click on the link to determine if it's used for chatting. However, your husband may have disabled the history function; in this case, you will not see any websites displayed.
Check to see if your husband has installed a webcam. Webcams are commonly used when chatting online. Look for icons on your computer's desktop that weren't there before. Determine whether any new instant messaging programs are installed, such as Yahoo Messenger, AOL Instant Messenger or Windows Live Messenger.
Download a "spy" software program, such as KeyLog Pro, if you want to take a more extreme measure. KeyLog Pro says that it "records every keystroke made on your computer on every window, even on password-protected boxes." You can instantly download KeyLog Pro for £12.90, as of December 2010.