SG, I would just tell her if she' hasn't decided to be honest about her affair and do the work to repair the damage then you have nothing to say and hang up.
Right now there is nothing she is going to say that is of use to you. It's just going to be more negatives and threats and intimidation.
The BEST thing for you to do is NOT engage her because THAT is going to worry her MORE than if you confront her right now.
You need to get your ducks in a row as far as exposing this and blowing it wide open.. SHE is giong to want to keep this all quiet as possible... so, Don't allow that...
Blow it open and she will be under super stress to run damage control everywhere.
Keep HER on the run until you know she's stressed out tot he max... THEN you call HER and tell her YOU want to talk...
Just ignore invitations to talk unless she' sends you a ceasefire note in email or something.. in THAT case, post the note here and we can analyse for you...
