I am going to make a command decision that I don't want to know what Mrs. Clarkson looks like, if there is one. RPS brings in the whole "Are we writing about the TV personae or the real people? Are the personae married?" issue, and I'm glad that in your fandom there's some peace made with it.

I really dislike "We conveniently got divorced/broke up before this story" or "Now that we've kissed, let me reassure you that my marriage is an open marriage" as a setup. The former feels like disposal of women (mostly; I backbuttoned out of a story wherein Stephen Fry was magically single for the purposes of smut), and the latter steps on my first-time kink.

If I had to guess, I'd say that OT3 shows up *more* in fandom than in real life because people who have more of a One True Love bent can get to Two True Loves more readily than Lots Of Loves That Are Awesome But Not Coequal.