Do you understand why these rules were put in place? The reason was to find a way to keep couples together to assure their children would grow up healthy. When it comes to any kind of organized population, in order to keep the needed population it was important to have offspring that grew up healthy to add to the population. Religions were formed to ensure population is maintained.

Masturbation was seen as a sin because there was a need to have both sexes engage to produce off spring. Keep in mind that years and years ago many children did not survive to adulthood, and many actually died young too only in their early twenties, so that meant it was important to produce many children so some could survive to populate. One cannot have a kingdom or tribe without people.