Is forgiveness actually subjective?

For instance many of us would think finding our partners in our bed with our best friend is unforgivable. I would too. But is it indeed unforgivable?

What if someone else were to have the heart to forgive both and work it out? Then who are we to say that's suppose to be forgivable and what isn't? What's unforgivable to many of us might be forgivable to someone else.

I've seen extreme cases where a parent was in court and actually forgave the drunk driver that killed his/her child. That's a forgiveness of the highest degree and indeed something I wouldn't ever forgive.

So saying ''that's unforgivable'' wouldn't be correct because there will always be someone out there that actually can forgive higher offenses too. So overall, is forgiveness subjective?

Updates
11 mo
Kent Whitaker for example forgave his son (and still visits him in prison) for murdering his wife and younger brother. He was originally going to be sentenced to death but the father pleaded not to and instead received life in prison.
https://www.youtube.com/watch?v=5lhIu2zo76Q
Personally (subjectively) that would be unforgivable to me but it's not objectively unforgivable because the father forgave him.
Is forgiveness actually subjective?
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