Catch him off guard one day and ask to see his cell phone. If he puts up a fight or refuses to give it to you or ask a zillion questions, chances are it's something in that phone he don't want you to see.
Step2
Go to myspace and check to see if he has an account. You can search using his first and last name or his email address. Look at some of his friends. If over half of them, or all of them have that "look at my booty myspace pose" you know the ones showing all the back instead of the front. Ask him about it. It's also a good idea to check out some of his friends pages and read their comments on their profile and comments on their pictures; your husband may have made a comment or two.
Step3
Here's the biggie...Ask him to log into either his myspace messenger or yahoo messenger or whatever messenger he use while you're there in his presence.
Step4
Install a spy program on your computer. Two of the one's I would recommend is PC Pandora and Spector.
Tips & Warnings
If you suspect your husband is cheating it is always a good idea to simply ask him, if he says he's not and you still suspect him, this is when I would use these techniques.
Enthusiast 
