The first step when you want to get help for your sex addiction is to admit that you have a problem. Likely, you will need to experience one or more negative consequences as the result of your sexual behavior before you are ready to face the fact that your compulsivity is out of control. Consequences may be legal (getting arrested), medical (contracting a sexually-transmitted disease or becoming pregnant), or emotional (relationship breakup).
Once you get to the point where you are ready to get help for your sex addiction, you have some options to choose from. You can make an appointment to see your doctor to ask for a referral to a therapist with experience in dealing with sex addiction. If you have been engaging in high-risk sexual behavior (one night stands, multiple partners, visiting prostitutes), you will likely want to be tested for HIV and other STDs.
Another option to get help for your sex addiction is to contact Sexaholics Anonymous. Chapters exist all over the United States and in a number of countries worldwide. Like Alcoholics Anonymous, Sexaholics Anonymous is a 12-step program. Members attend meetings to get the support they need to stay "sexually sober." Monogamy is encouraged for group members. They are asked to either abstain from sexual contact altogether or to be faithful to their spouse during recovery.
You can also look for treatment centers that offer help for sex addicts online. Both inpatient and outpatient programs are available when you want to get help for your sex addiction. Your options may be limited due to your financial circumstances or the level of insurance coverage you may have available to you for treatment for addictions. Be sure to get details about the types of treatment programs available from various treatment centers (individual sessions and/or group therapy) before you make a final decision about where to get help for your sex addiction.