You are not alone. Many struggle with this, but you need to treat it as an addiction and seek recovery just like an addict would. There are groups like AA for alcoholics, NA for narcotic users, and even Sex and love addicts.
Certain chemicals in your brain are released when you engage in this activity, so you become addicted to that chemical release. There is hope however. Even lifelong addicts can recover, but you need help. It is very difficult to do alone. You will probably need a sponsor to help you through.
You could start by looking in your area for an AA group. Going to a meeting with others that struggle with addiction and hearing about stories of achieving sobriety can form a good basis for your first step. There may be someone there that can become a referral to another group that is more focused on your issues, but even if there wasn't a sex addict group in your area (which are completely anonymous), you could find the same principles in AA: 12 steps to overcoming this life ruining disease.
You must not lose hope, there is a way out. It will require humility and acceptance of self — even as a recovering addict. The beauty of the twelve steps program is that God is central to your strength in fighting temptation.