Is lying a deal breaker in a relationship?

[philosophersdilemma]

Can you be with someone who lies to and actively hides things from you all the time? I really am referring to lying about or hiding things that matter, like talking intimately to friends of the opposite sex or cheating.

What HAS to be told in a relationship?

[melissarose8585]

No lying about the big stuff whatsoever. We try to be brutally honest. I mean, sure there are some white lies (of course I was in bed before 3, or no, I didn't forget to put the toilet paper on the holder) but if it is remotely important, we are honest. Lying is a deal breaker in my relationship.