YES, he needs to be empathetic to her feelings (about HER "god, I really screwed up" triggers), and YES, he needs to not sound so NEEDY in how he handles these exchanges (I like Rob's humorous suggestion).
But work contact with OM is a problem. I'd try to concentrate your efforts on THAT PART of the equation, and try to give grace as much as possible in the other areas.
As betrayed spouses, we always want the formerly-wayward spouse to "feel our pain," but in almost every case, it's just not productive.
