This saying alludes to envious people who do not enjoy good, nor does it allow others to do it. The origin is in the fable of Aesop "The Envious Dog", where a dog tends an orchard for its master, and keeps all the animals that come to eat from it, so an ox criticizes him that without being herbivorous is preventing other animals from feeding on their vegetables. In Spanish she became more popular thanks to Lope de Vega's work "El perro del hortelano", where Countess Diana cannot marry the commoner Theodore, but also does not allow him to do it with his maid Marcela. There are a couple of variants that I comment without too much foundation. There is a rhymed version (closer to the structure of a saying) such as 'The dog of the garden does not eat or let the master eat', which undermines the original meaning, but would have to do with a parodied form where the verb was "cojer" and which had its own. . . Fable. On the other hand, I was once told that from the latter a pun was made with "hortelano" and ". . . the ortho and the anus" , which would be an etymology of the word 'ortho'. But I never found a written reference to these, so I guess they wanted to fool me like a schoolgirl. See old dog does not lied or let you.
