So I went to Darkwater Crossing in order to start a miscellaneous quest for Sondas Drenim.
However he does not mention the issue / quest, neither do I get an option in his dialogue.
Any suggestions? Am I doing something wrong?

I've never run across that misc quest, so without more info there's not much to say.
If it's just a misc quest, you may just have to ignore it, unless there is any other info: what do you have to do for the quest, find an item? Defeat a specific target? Does the quest have a marker you can follow?

You are suppose to speak with Sondas. He will instruct you to deliver a letter to the White Phial in Windhelm.
But the option does not appear.

http://www.uesp.net/wiki/Skyrim:Deliver_Sondas%27s_Note_to_Quintus

This is all i can find about that quest for you just days Deliver [Item] to [Target]
Wearing the Amulet of Mara will open marriage options for him

Hmmm... could be a glitch.
Can you revert to an earlier save, or reload from a cell back to where Sodas is, to see if when the cell he's in refreshes he's "fixed?"
Those are the things I would try, in that order. If that didn't work, I'd probably go do other quests for a while and stop back by Sondas later. And if that didn't work I'd probably curse in every language I know curses in, under my breath...