Chemical Addiciton part

Currently learning to navigate through my husbands addiction to porn. While he is out of state right now and claims to have stopped, all I have is his word that he is stopping the use of porn. I have found out though that while he claims to not be actively watching videos on a device or having dvds. However he admits to still masturbating using the videos he recalls in his head. I feel this is still using porn even though he claims it is not using the computer or videos to seek it out. I also wonder if it's wrong to ask him to stop masturbating until he can control that image recall, but I don't know how that works.