I have played through the game 4 complete times, at least twice that many in half-finished games. I recently started playing again for fun, and I got a quest in temple of Mara in Riften where I help some people hook up and find love.

I have NEVER seen this quest before! Did I just miss it all those other times, or did I do something different that I'm not aware of?

It's always been there. I only did it recently for the first time myself, I just wasn't playing characters that would do a quest like that lol. Pretty cool though, isn't it?

You just missed it, because there are no prerequisites for it whatsoever. You just need to speak with Dinya and she gives the quest.

It's a very important quest too, because the reward is indispensable.