In 1935 two alcoholics, Bob and Bill, came up with the idea of helping themselves deal with the disease of addiction with a set of 12-steps. At any given time AA has over 2 million active members worldwide; this is an incredible feat for an organization that is built purely around principles which doesn't do any marketing or outreach.
In the 1970's Sexaholics Anonymous (SA) was born to give sex addicts a similar organization where they could come together and help one another achieve (and maintain) sobriety. SA was loosely built on the same 12-steps that Alcoholics Anonymous was built on, and this was made official in 1979 when AA officially authorized SA to use the Twelve Steps and Twelve Traditions.
Sponsorship
12-Step programs generally recommend newcomers work with an experienced member in the fellowship. This provides guidance to the newcomer, but it also helps people with a lot of time (generally at least a year of sobriety) remember the blessings they've found in recovery. Finding and choosing the right sponsor can make a big difference in your recovery journey. Most meetings will have a sponsor coordinator, or else they will have everybody who is willing and able to sponsor raise their hand during the meeting to help identify who newcomers can approach about becoming a sponsor.
While sobriety from drugs and alcohol is pretty easy to define, it isn't quite as easy to come up with a universally agreed-upon definition for sexual sobriety. As far as 12-step groups go SA has a rigid definition of sobriety - no sex with self or other people outside of a legally married man and woman. This excludes gay couples, even if they are married. Or couples in a serious committed relationship who haven't been married yet.This caused some divisions in the brotherhood, and in 1991 a similar group, SRA (Sexual Recovery Anonymous) which does recognize same-sex couples in a committed relationship.
The Format
The format for SA meetings is similar to other 12-step meetings. They typically start with readings from the basic literature (read by anonymous members in attendance). Starting in early 2020 with the onset of the Covid-19 pandemic, many of these groups started meeting online (primarily through Zoom), although many chose to continue meeting in-person where still possible. Hybrid groups meet in-person, but can also be joined remotely.