You're absolutely right - only Callista is the adulterer here. Newt gets a free pass (or two, in this case) and manages to slither through - he wasn't Catholic at the time he was fooling around with Callista behind Wife #2's back. He only became Catholic after he dumped Wife # 2 for Callista. Saved by a technicality in Catholic doctrine! As Dana Carvey's Church Lady would say, " How conveeeeeenient!"