Okay, Now I'm Stumped. HELP

Do you use MCC? I would try using it to change the relationship. I also believe that UI cheats will also amend relationships.

I tried MCCC but the only relationship available is father or son. I'm contemplating taking the entire family unit into the Gallery just to download them again. May I scream, yet?

Did you turn on CAS full edit mode before going into CAS? What ages are the sims?

Yes, I did. I've also just read a very interesting article on how to fix this using MCCC. Seems I need to first delete the relationship, then go into CAS to create it anew. Then fix the love/friendship levels after the fact. Wish me luck. Should I end up taking them to the gallery, I might as well go back in time to the save that has them first arriving on Earth. As they will lose all of their relationships with other Sims. They just now have two allies, too.  Sob.

ImMendota​  In the reading I did on UI, seems all you can fix is the levels of romance and friendship. I saw nothing that would make them married again. OOFFDDA, but thank you so much for pointing me in the right direction.

I spent the entire day going back to square one, as it were. I had the older generations of the Cantrell family. I broke them down into family units, so I could create King Aaron's parents; King Nicholas and Queen Alice; and King George and Queen Christina.  This gives me four generations counting Joseph, Sr. Cantrell and his wife, Louise.  I've since made some clarity. Since his uncle is the first Joseph Allistair Cantrell, I've made my Joseph Cantell, II. I think in the long run this will help others keep up. I made certain Joseph II and Louise were married. I played with the first group, so I would have urns of King George and Christina. Broke the family down again, so I could have urns of King Nicholas and Alice; then just King Aaron and Julianna and their kids were left. This was the third group.  I played them because Michael, Joseph's next younger brother died as a kid (teen) he worked out far too hard. Then their father died of old age. Lastly, their mother died of a broken heart. I had Joseph A. Cantrell I, take the throne, while Joseph Cantrell II, left the family.  

After all of this and also making certain my Joseph had his full family tree (which he did, yay), I emptied the faux Joseph's inventory so my Joseph could have the urns.  Then I deleted the doppelganger. Joseph II still has his full family tree. (yay).  But after all of this rigmarole, suddenly Joe and Louise are cousins. I decided to just stick with the new one, since it shows more generations on the tree. 

I can only hope that sometime in the cough-cough, near future, EA will sort this out. Pretty Please!

You know how I mentioned my one couple is now listed as cousins? Yeah, weird.  I did give them a new relationship tag. I added spouse, but I'm uncertain if that has changed anything. Louise got a phone call from someone who wanted to know why she's still hanging out with Joseph. Face/palm.

I checked on the other couple I moved to Ondarion. They moved into Verdemar. Curiously enough, they are still listed as spouses. A-hem.