First play in Skyrim on my PS3, I ran into Astrid through normal means (don't want to quest spoil), after first couple run-ins with her, She was definitely the NPC I wanted Adam to marry, but that didn't go so well, as I'm sure most know... I was so disappointed

Uh, Astrid is certainly not on the list of people you could marry anyway, as she is already married.

Well...I thought about Jordis. But she died in some Falmer cave. Out of respect, I took off her clothes and sold them to a Khajit caravan.

Falmer are probably using her in some ritual in order to summon The Great Mudcrab.

If they succeed in summoning The Great Mudcrab, I'll marry it. In a sense, Jordis' soul is inside the Mudcrab. I just need to wear my amulet of Mara, and The Great Mudcrab says with a thunderous voice: "Is that an Amulet of Mara?"

M'aiq wishes to marry Atahba, but he can't.

My Precious... Lydia, was taken from me on the way to the Talos shrine in Eastmarch. My character was supposed to ask her to marry her when they got there.

Sylgja is, unfortunately, far braver than her pickaxe is an effective weapon. I have to remember to only enter the mine late at night. So yes, I've had to reload a few times.

I only ever marry her or Muiri, and I think Muiri stays marked as essential.

I had an idea for a vampire character that would marry Harkon (with his wife living... elsewhere, he's as good as divorced, isn't he? ). If that even would be possible with mods/console commands, of course.
Then I remember that that marriage won't last long even if I side with the vampires in the DG questline.

Except for that, my characters have had a tendency to fall in love with unmarriable characters, but I don't think anyone has died. (Except for the occasional follower, but if it's a follower I plan to marry, I always reload.)

Hmm....I don't think so...The only one I can think of is senna but she died because of that giant ice spear to the face...(It was an accident I swear to Talos.)

Now that i'm on PC, I always marry Serana.

You can sleep on her bed at least