I had an ex on the spectrum who thus had a very rigid approach to the concept of 'lies'. I.E. there is no such thing as a small white lie.
I had a Twitter account (nothing drastic) she never knew of and by the time things had progressed I deemed admitting to having it would be seen as a lie (and due to her psychology, up there with basically admitting to having fucked her sister or something), and result in a spectacularly exhausting fight/argument/probably break-up.
Of course she found out (clever & paranoid girl) and at that point I pretty much just went with it, figuring resistance would just create a tiring miserable situation that would still ultimately lead into a split.
She was a interesting girl, and I was bummed out, but ultimately I'm not too distraught, she was awesome but holy fuck could it be a mental minefield being with her.