If they are wedding photos, keep 'em until the divorce is final.
Seriously, I'm solidly in Blansky's camp as well. I have kept almost all my negs for the last 28 years. Yes, I even kept the ones that got divorced... Ya never know.
In my dance photography business, I have sold prints from negs that are 20 years old. They are indeed an important archive for the history of ballet in Puerto Rico.