Stuck in the Night Mother’s coffing during “Death Incarnate”

Very odd - I found the wedding ring on the witch myself, so it does sound like a glitch. Unfortunately as an Xbox user you can't abuse the console into solving the problem.

If I remember correctly if your speech is high enough, you should be able to persuade/intimidate Ysolda into telling you the next location for the quest. This looks to be your only option if you don't want to pay.

It could be a Z-Fighting issue similar to the flickering mountains glitch. If you altered the .ini to reflect the sky, I recommend going back to original config options and choosing to use the tool below instead, which has a simple checkbox for sky reflections.

If you don't have it already, I recommend getting the Skyrim Configurator: (http://skyrim.nexusmods.com/mods/814/?) It's basically the configuration .ini with an easy to use interface.

Find the options that involve fixing Z-Fighting (in red text) and maybe Water effects, it may just be that your video card doesn't like one of the water settings you have. Let me know if you find anything out! I'm curious about this glitch now.