The 12 step groups are a great idea, I think some even have online meetings also.

There are also good books out on this topic. At amazon.com you can do a search on "sex addiction" and look over what comes up, lots listed. You can then either buy through their site or another bookstore, and/or can get them through your public library. Some books are how to workbooks, others are first person stories.

Sex Addicts Anonymous
Sex and Love Addicts Anonymous