I have never seen Nick without Tiff. My guess is she won't let him out of her site.
Or possibly Nick does not have a drivers license and needs Tiffany to take him places.
Of course we know Nick does not have a regular job so that could be part of the issue as well.
Or...maybe Nick is smart enough to not let Tiffany out of HIS sight.
BTW Rick, I was not offended by your "rack" comment. I was offended by that other guy's (what was his name?) snarky comments.