As a non-jw who has a lot of issues with family, thank you all very much; this thread has clarified my thinking.
On sin and not-sin, I'm still uncertain. But for me, forgiveness comes with understanding where the person-who-needs-to-be-forgiven is coming from. This certainly does not mean instant return of trust (wish it could! )
It can also mean understanding what I did to contribute, or allow it to happen. And forgiving myself, which is the hardest of all.
To bring things back to something relevant to the forum, I'd also say that my fixation with keeping contact with my jw SIL had a lot to do with avoiding these painful areas. And I can see how attractive the wt could look to someone lonely and trying for a new start without doing the hard work of forgiveness.
Retro