@hanstand,
The use of that apostrophe is fine.
Frankly, that writing is not awful or even ungrammatical. Personally, I'd write it as '
each', (not every), but that is a nit.
Secondly, you proposed a wordy sentence. I'd correct it this way.
Quote:"The email for each user (or addressee) can be found in the directory."
or even more simply:
Quote:"Each user's email address can be found in the directory."