So I got married to what's her face, sister of the dude from riverwoods trade shop. And...I killed her I wanted a spouse that would go on adventures with me! But now it seems that the amulet isn't working anymore!! Does anyone know how to get remarried??

you can't remarry it's impossible

reload a save from before marrying what's her name and marry mjoll from riften....

I wanted to marry Mjoll. But she hates me. She asked why I was in Riften and I asked about the Thieves Guild. Then she wanted to know why I wanted to know about it. So, I told her I wanted to join them. So, now when she sees me she goes, "Oh, it's you. You're not here to rob me are you?" And if I stop to talk to her she tells me to bugger off.

You shouldn't tell everyone about your criminal career, silly.

Mjoll is lame. She'll just become a shield to protect your targets from your arrows. Plus, that guy that's always tagging along with her actually moves into your house with her! Too creepy for me.

If you want a wife that will adventure with you, marry Aela. She rocks.

lame? the only marry-able follower/companion that cannot die? and if you keep hitting her with arrows instead of your targets you stink at archery. not to mention there is a way to keep the creepy guy following her from moving in.....

Murder? MURDER!!!!

Incorrect. Aela can't be killed either, unless you complete all of her radiant quests (Same as any of the other companion leaders). And my skill with archery has no bearing when my follower is constantly moving around during battle, including after the arrow has already been loosed. There's nothing you can do about that. A proper tank knows how to position the enemy so that their ranged partner can get easy shots at their back. That's what I do when I am the warrior. Besides, Aela is far more attractive than Mjoll- unless you're into "husky" women, that is. I'll give her one thing- she's certainly a "manly" gal.

Wait, wait, wait. She has a finite amount of Radiant Quests?

I don't know if it's properly called "radiant quests" or not. After you become harbinger, you get a quest, "see the companion leaders for work" in your misc quests list. If you track it while one of the companion leaders is your follower, you even get a tracking arrow over their head (can be pretty useful for finding them if they get caught on terrain somewhere back, and you didn't notice). But yes, I've heard that there is a finite number of them, and when you finish them all, those NPCs lose their essential flag. But, as long as they have quests to give out, they are considered essential, and can't be killed.