The difference is that in criminal cases, you can say “I still think the perp’s an SOB and I don’t forgive and I want to throw the book at the scum”, to some social acceptability. This comes up in death penalty cases, where there’s some pressure for grieving relatives to say soothing things, and if they say things like “I’ve heard the sob-story, and I still think the murder should die a slow painful death for what was done”, that sometimes draws disapproval, claimed to be vengeance, not “healing”, etc.

I suspect it won’t be acceptable to say “I still think my ex-spouse is sleaze”.

I wouldn’t say that there are common reasons criminals give but many talk about their background/upbringing. Importantly, many express remorse and hearing a sincere apology makes the victim more likely to forgive.