It's sometimes such a fine fine line with the lying. :-/
I'm a big one for being completely honest. I HATE lying and other than that I suck at it too. LOL
But then I have a world where I don't have to explain anything to anybody. My mom is old and we don't talk about the specifics of my relationship with my husband. I don't have anyone to explain anything to... but then I don't have family I share days and holidays with either. My m-in-law most likely doesn't know but she knows her son and I doubt she'd be surprised. We just haven't been in the position to HAVE to explain anything yet.
Long story short (sheesh), I understand where you're coming from.