Thanks all for your feedback. This was how I perceived the situation, but a trying to get a bit of space and objectivity. A couple more details.
First, my husband, his girlfriend J, and the B2 met for several hours yesterday to talk things out. My husband was shocked to discover that after three or so hours he was "drawn in" by the B2's rationale. The rationale for taking the two week hiatus from the relationship was, again, that he feels anxious and "can't think straight" when they are together. Additionally, he blames J for his feelings and holds her responsible for making him feel better, and has said things like, "if you don't give up your overnights, that proves to me you aren't committed to our relationship."
I offered to be present at the meeting, having a similar vested interest in the health of all relationships, and B2 panicked because of my profession (I am a doctoral clinical psychologist) because he didn't want to be "analyzed." I have determined that he didn't want someone calling BS on the behavior.
I have had several discussions with J indicating my concerns about the controlling nature of the behavior. She has stated she wants the trial separation to be "one last chance" for B2 to shape up his act. I have expressed my concern that giving one more concession (there have been endless concessions) is simply a reinforcement of the behavior and will likely encourage continued behavior. And, he will certainly be more "nice" because he will be getting what he wants, compliance.
Fuming and sad...