writes:

Anyway, any suggestions on my situation? I'll try a second coat of
primer and paint and see if that helps, but not optimistic about that.
Should I try getting ALL the old paint off? If so, should I use some
solvent as opposed to sanding, as the sanding of the peeling part
didn't seem to touch the stuff still adhered. Thanks.

Contact a tile refinisher in your area.

I had this process done, and have been very happy with the
results:
http://kottkoatings.com/koated_gallery.html

There are similar competing processes. Look for tub and tile
refinishers in your Yellow Pages.

Caveat: I no longer own the home where I had this done, but talked to
several very happy repeat landlord customers who wer epleased with the
longevity. The cost was very reasonable too.

Best Regards,
--
Todd H.
http://www.toddh.net/