I'm some how agree with your husband.....I think you should not dig into the old crappy memories....while you can't do anything about it?
I'm afraid that your girlfriend has the similar issue with the guy and she just wants to forget about it or maybe she forgot already....
I, myself, usually forget the bads and just keep the goods in my mind....and so many times when friends and family asked me for so and so in the past, I just simply don't remember it!
take care of yourself and try not to think about what has happened with that guy...thank god he's dead now and most likely he has a breakfast with devil right now!
M.