Solved
Marriage to a ghost prevents a new one even after he disappears forever
A husband of my Sim unexpectedly died of laughter (what a drag). I just made them and I needed him to progress his Mischief skill quickly, didn't even notice the event, just got surprised when he van...
Your best bet on getting this fixed would probably be installing the MCCC mod and clearing all relationships. I'd suggest saving your game right before doing so, so you can go back if needed. If you really want to be safe, make a back up: https://sims4.crinrict.com/en/2014/09/backups/
What JP is saying is correct, that is the bug report that belongs with what you're experiencing, only the workaround wouldn't work for you.
