You are in love with a sexual addict he is very good to you how can you help him you have researched and this is a seriouse addiction?

There is no way for a male to substitute sex, but the best option is to explore all of effects before you try and find a way to suppress the addiction. "No" is simply the cure, but if its more than just a constant craving, and if it seems like sex deprivation is emotionally harmful and discomforting, then you may need to seek some kind of medical assistance, unless if there is something beyond sex that the addiction is masking. He may think he needs constant sex for a confidence booster, or there could be something he is trying to escape.