Those “headed for the cheatin’ side of town,” in the words of the Eagles, are having a lot of help these days — most of it on the Internet.

The business of extramarital affairs is a booming one, with a lot of online companies more than willing to play a part for a price. A slew of Web sites have cropped up offering dates, matches and even lies to the already-married who have strayed — or want to.

Among them: Philanderers.com, MarriedSecrets.com, PerfectAlibi.com (with good stories for the unfaithful to use to cover their tracks) and AshleyMadison.com, site of The Ashley Madison Agency.

That last site lures the unfaithful in with the slogan “When Monogamy Becomes Monotony” and is the biggest cheating site in town, with claims of 160,000 members. It puts philanderers in contact with potential paramours just like any other dating site for singles does — with pictures, profiles and instant messaging.

It even offers affair advice about safe sex and how to avoid giving out home or work phone numbers when meeting someone. Those who run the site say they aren’t encouraging infidelity, but they understand it and are providing a service to those who have already decided to cheat on a spouse.

Many therapists worry about the consequences of infidelity becoming an Internet industry.

Family counselor Brett Williams said cheating Web sites are making it easy for people to stray and helping to ruin families.

“They’re basically destroying the fabric of our society,” Williams said. “Our society is built on family units. Once that decays, we’re not going to have much of a society.”

Click on the video box at the top of this story to watch a report by FOX News' Trace Gallagher.