Have you ever apologized to someone you wronged for a very long time, or received an unexpected apology in a similar way?

Such a long title.

Basically I'm wondering if this happens IRL, and how. I've heard countless stories of people who hold a grudge against family members /ex partners/ ex friends/ neighbours etc. for years, and they do horrible things to each other. Or maybe just the cold shoulder can be rough especially for such a long time. But not so many stories of people in these situations who suddenly talk things out unexpectedly, out of their own will and not because they kept getting nagged about whatever happened.

I've also heard about people who screw up big once, never acknowledge or apologize, then everyone puts the episode behind and moves on. But I've never heard about suddenly this person perhaps decades afterwards just actually addressing their screw up and apologizing.

So, have you ever received one of these big, unexpected apologies? Or have you ever apologized for something you did you never thought you would want or dare to apologize for?