Subject: Depends.
Author:
Posted on: 2011-05-14 17:50:00 UTC
If you've got more than a few lines of basic statistics to say about them, then a page is probably fine, but in cases of "X was Y's former partner until Z happened to them" or similar, just a mention on Y's page is probably sufficient--especially if they never appear in any stories.
~Neshomeh