I've struggled with this more than I would care to admit.
But what's more shaming about it is that I only typically think about it when I begin feeling frustrated that someone else is doing it to someone.
I'm sure you've seen it. Someone who is reminded of their past sins and failures - not by their own sorrowful conscience - but by their friend, their spouse, sibling, family member, co-worker. We hold onto other peoples sins because we feel rightful in it.
If you have sinned against me I have the right to remember it forever, and to require you to take steps to prove it will never happen again even if it means it destroys you in other ways. Even if it means you must always remember you're going out of your way because you've sinned in the past. Even if it means you'll never be able to get past the sin and truly forgive yourself and MOVE ON beyond the sin - because you're always paying the cost of your sin.
I hate it when I see it. Some poor person intent on doing the right thing yet always taking extra steps to prove trustworthy, since in the past they have not. It makes me angry.
It makes me even angrier when I fail to see it in myself. I declare myself righteous and entitled to extra efforts because of what someone has done. And it just isn't true.
Once I've said the powerful words "I forgive you", that is it. No more lording it over them, no more chastisement and snide comments. No more sharply pointed jokes aimed ambiguously at my victim.
That's not what Jesus taught.
So when you say you forgive someone - the rest of the story is now between the person and God. Let it go, trust, and accept.
God really can handle the rest.
And NO ONE deserves a life time of reminders of their past.
Now I just have to stop actually doing it.
It's probably going to start with my tenant who just put the "check in the mail" again. :)