Until the basement floods and the server goes offline for a few days
That’s what backups are for.
or botched upgrade that’s failing quietly;
See above
over zealous spam assassin configuration;
That’s an assumption that you’re using this specific product.
What’s funny is you think that all of this can’t happen to your stuff on Google’s servers either for some reason… Say the wrong thing in a Youtube comment? Boom whole google profile banned. All your emails are gone too.
Or random software that interfaces poorly with each other (https://support.google.com/mail/thread/142335843/all-of-my-emails-have-disappeared-how-can-i-recover-them?hl=en)
Well… No offense… but duh? It’s not like OP can migrate his spouses “Spouse@gmail.com” address to his mail server.
I was under the assumption (and I could be wrong) that OP owns the domain… And wants to run their mailboxes. If she wants to keep her own mailbox and use it, just forward it to her gmail if that’s what she wants. I’m also not insinuating forcing someone into something.
I own my domain(you guessed correctly) and host my own emails. My spouse does use an inbox on my server(actually a few)… If she didn’t want to anymore she can open a mailbox where-ever she wants… and I’ll even forward whatever I get to her. That’s it. Wouldn’t stop me from running my own inbox on my own server. And I’m not forcing her to do anything at all. She can use it or not.
This is the mentality I have when I made the previous comments. Just forward her stuff off, she can go wherever she wants.