1
general::
Phrase(s): dog in the manger
one who unreasonably prevents other people from doing or having what one does not wish them to do or have. (From one of Aesop’s fables in which a dog—which cannot eat hay—lay in the hayrack [manger] and prevented the other animals from eating the hay.) • Jane is a real dog in the manger. She cannot drive, but she will not lend anyone her car. • If Martin were not such a dog in the manger, he would let his brother have that dinner jacket he never wears.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
One who prevents others from enjoying something despite having no use for it. For example, Why be a dog in the manger? If you aren't going to use those tickets, let someone else have them. This expression alludes to Aesop's fable about a snarling dog that prevents horses from eating fodder that is unpalatable to the dog itself. [Mid-1500s]
American Heritage Idioms