Withholding sex is about control. It's a passive/aggressive way of expressing anger. Someone who withholds sex will imply by their actions that they have a lot to give.
In the beginning, your wife or husband was charming and quite appealing. You had no problems with intimacy in your relationship. Both of you couldn't keep your hands off each other. You felt desired, cherished and loved by each other but unfortunately, this is no longer the case with your relationship.Obviously, something has really gone amiss since those days of your early marital life.