Same here. Although I didn't start playing until after the Halloween quests started. I can't see my husband's town (he could see mine), or I'll drop off his list. It's not predictable: sometimes we'll both be able to visit each other, sometimes one of us will disappear (usually him). My other Facebook friends are still there.
We're both using Samsung Galaxy S4s, same OS & Tapped Out versions (most recent).
ETA: I've tried logging out of FB & back in, clearing the Tapped Out cache, restarting the phone, and uninstalling & reinstalling the game. At best I get him back for a few hours, and then he's gone again.
