tell use-package not to install stuff

[emacs-list-18]

Hi,

 i need a little help to convince use-package *not* to install auctex
 when i have tex disabled in my init.el.
 init.el is hosted in a git repository, and is used on various machines.

 The init.el snippet in question:
 
  (use-package tex
    :if (my-enable-latex)
    ;; defer loading till on of the following commands is used.
    :commands (latex-mode tex-mode)
    :ensure auctex
    :config
    (do-some-setup)
   )

  The thing is: tex and auctex are not loaded if my-enable-latex returns
  nil, but it installs it if it happens that init.el gets
  compiled. Hmpf. Not what i want.

  What i need is this: On a new install of emacs (on a vm, for example)
  with my init.el i want use-package to do nothing when
  (my-enable-latex) yields nil, no matter if init.el gets compiled or
  not.

  I think i misunderstood what use-package does here, can anyone bring
  me some enlightenment here, please? :-)

regards,
Chris