I'm not sure where you're posting from, but there's no "Unlimited Expansion" thread in the GalCiv2 forums. You can access the second page of the thread you're looking for by manually adding the page number to the end of the URL for now. For instance, this thread from the GalCiv2 forums has a URL of "https://forums.galciv2.com/354771". If there was a second page, you could add "/page/2" to the end of the URL and it would look like this..."https://forums.galciv2.com/354771/page/2".
It should work from whatever forums you are in as well.
Thanks to Fuzzy Logic and Mumblefratz for pointing this out. +1 karma to both of them.