What disturbs me about your fiance's behavior is that is secretive. Generally, secretive behaviors (such as this one) are signs of addiction, and it's best that you talk to him about this BEFORE you get married. The last thing you'd want is to have his addiction interfere with your intimacy, which it will if not addressed. There are a number of excellent 12 Step programs that deal with sexual addictions, and you might want to check them out and attend some meetings before you speak with him about this very sensitive topic. Many people have resistance to admitting that they have an addiction, so the more informed you are the better. If you would like more info about these programs, let me know.