So I found this fort just up from the Antronoch (sp?) stone called mistwatch with some fairly hard bandits. Then I found a husband who that thought his wife had been kidnapped but it turned out that she had ran away and was actually the leaders of the bandits. She wanted me to get her husband to go away with no death so I gave him the ring saying I had found it, he runs off around the corner and there is an explosion like a fire rune killing him. I think hey nice touch but what a cold hearted minx! So I setup (I am a battlemage) then attack and kill her.

Later I am selling and find the ring she gave me to show her husband to make him go away. Now I feel guility (well my character does anyway). Did I kill an innocent (of the crime I declared her of)? If so what killed the husband?

I came across this side quest a while back. I talked to the husband and agreed to try and "rescue" his wife. When I got to her she said she didn't want to go back to him anyway and, as she was a bandit leader, I fought and killed her. Found the ring on here body and took it back to here husband. I was thinking that there's be a few speech options with him, such as "I couldn't find her" or "she'd been killed by the bandits, but here's her ring" or such. Instead when I spoke to him the only speech option is "She attacked me so I killed her".... not very satisfactory I think. You should at least be able to avoid letting him know that she'd gone bad.
BTW, I avoided risking getting the husband killed by telling him to wait while I looked for her.

Well he was pretty adamant about no coming with me so he didn't die in battle. I honestly thought she had gave him me an enchanted ring attuned to him somehow that was designed to kill him. I was actually hoping for something like this as I can see great quest potential once the CK is released.
I guess the option to protect the husband from that knowledge is to not fight her, but as I said either way he ended up dead.

You shouldn't have killed her. If you pay attention to what the bandits are saying, they are working on their own will without her ever knowing what they are doing. She is just a sword for hire recruiting other people like her. Beth. should have really made her a companion, but there are suspicions that she maybe involved in a future DLC.

Just found a finished this one. I thought I'd kill her or the loot that is bound to be in the "Boss chest" in her bedroom then lie to him to spare his feelings. Turns out that there was no chest, no loot, and no option to spare his feelings. Then the idiot decides he is going to kill me with his bare hands and I can't get him to stop hitting me. So he meets Chillrend (at least I didn't take his soul). A most unsatisfactory ending to what could have been a nice little quest.

Got 74 septims from a fence for the wedding ring though.

I helped her and told her husband she was dead on one playthrough and she told me that she owes me one and thinks we'll meet again. Does anything ever cone from that or has anyone seen her again? I haven't so far.

Side note for necromancers, if you kill the wife she is a great Thrall. Really strong and continues to level with you.

I found out about Mistwatch about some woman in rags coming across me and telling me about the place, I investigated and spared her and told the husband I could not find her, all without drawing blood on her or him, despite being a leaning evil character.

What I was really curious about was if anyone else had the exploding ring (if that is in fact what happened) occur when the husband runs out to go search further.