Originally Posted by
AJBopp
If a given show is about a couple being together, it often works pretty well. If a given show is about a couple getting together, then they keep having to invent ways for the couple to never quite complete that journey, or the premise of the show is done.
There are a handful of shows where they successfully transitioned from "getting together" to "being together" (Castle comes to mind), but in general there seems to be a fear to even try. They'd rather risk increasingly implausible stories that get in the way of their relationship (which Castle also did for a time). The Big Bang Theory has also managed it pretty well.