Actually, that background makes me think it less likely that it has anything to do with any current goings on with OM.
I'd think (I told you I make up background stories with the best of them...) her sister called her on the A and lying to you, gave her a hard time all around. Maybe told her she had to be honest with you, etc... Any pressure to really confront herself would indeed make W feel uncomfortable and have a need to avoid you until she can rationalize her past actions again. Is there anyway that her sister knows about OM or at least that you and W were having problems?
I can't believe you didn't ask her about the convo with her sister, lol. *What a man!*
