Navarro is right on track for how to fix it. The one thing that cannot be done here is to "unmerge". Once a merge has been completed, it is a done deal. You will have to add a new profile for the wife of the elder Edmund and, if any information in the merged profile, now the wife of the younger Edmund, is about the older one then you'll have to make the changes to the biographies of both to set things right.
Sorry you had this badventure but don't despair - we all do some bad things - without mistakes there would be no way to learn. You did the right thing, coming here to ask - hope to see you back here often!