W finally emailed. She says she was distraught, which is why she went silent. I now see that she had been in the house and removed a large box of her stuff that I'd packed. I am guessing that she was upset not just because of the lock on the door but also because of I've started to pack her things.
I'm sure that the reality of moving her stuff clashes with her fantasy of living unencumbered in her apartment while using our house as a storage space. Still, as she continues to move things out, it feels worse... it feels like the more embedded in the apartment she becomes and the more that space turns into "home", the less likely she is to come back.