What is the ruling on someone who masturbates while engaged, and does this entail the dissolution of the engagement?

Masturbation, also known as "al-adah al-sirriyyah" (the secret habit), is forbidden (haram) and entails physical and psychological harms. Despite its prohibition and danger, one who practices this habit is not subject to a ruling divorcing his wife because of this act. Divorce only occurs through uttering words that explicitly indicate it, or through a metaphorical expression accompanied by intention, or by a ruling from a Sharia judge or whoever acts in his stead, for a legitimate reason that necessitates it.