I think it's OK to hide the icky history as long as we do not let it influence our relationship.

For instance I am a BI guy, no STD, haven't slept with a guy in over a decade, won't cheat with guys. My BI past won't pop up to haunt me.

The only part of my BIness which can ruin the relationship is my partner feeling ick for it.

So if I keep it a secret, and it doesn't create the ick. No harm done.

However if my BIness is revealed and my partner feels the ick, I did a horrible thing.

So I think it is OK to hide icky past, but only if we can really keep it a secret.