Well, some things from the past are good to know and some aren't....
For example, I wouldn't care to know if my gal had a huge black cock rammed up her asshole or anything....
But, knowing, for instance, that she's had sex with another woman could prove to be valuable information if you're looking to coax your woman into a 3-some....
The old saying, "Don't ask a question that you don't REALLY want an answer to" hold true though... because once you open Pandora's proverbial box, there's no closing it!