@MsSol65 I don't mean saving a sim to the Gallery (which, as Playalot already explained, saves skills but not relationships).
I meant to use "Save as..." to save a separate copy of your game file, rather than "Save" which simply over-writes your current save file.
Everyone plays differently, but I'm playing a multigenerational game where I rotate between six different files.
Every time I start a new play session, I "Load" the most recent save file but, when I later save, I "Save as" to a different save file and use it for the current play session.
I was hoping you might have an earlier save file where you hadn't moved out the ex-husband yet.