I disagree. You need to BUST THE AFFAIR, exposing it aggressively, and let her know this is the LAST get-out-of-jail-free card she gets.
There's no need for your "Oops," Optimust. You were COMPLETELY within your rights to state your boundary, and in fact I thought you were even way too wishy-washy about it.
Right now, she knows if she throws the "D-word" out there at you, you'll back off. You must have taught her that. Time to go "Robx" on her, and say "You know what -- I agree. I think it would be best that we divorce. I value myself too much to put up with this kind of crap behavior again."
