Could this be a tactic on her part. It just seems very extreme to throw out the marriage and damage the kids, split up the stuff because "she'd" feel too guilty about your pain and issues. I've never heard that one before.
How old are your kids and do they know she has a boyfriend ?? If their older kids how do you explain this? I'd let/make her explain it to them with you being present to prevent distortion.
I really hate to be threatened or blackmailed and once that happens the gloves come off and the game changes ....so you might want to remind her to be careful what she's wishing for. Divorce can be a messy business ...once lawyers get involved the game begins ...their game can spin things way out of control before anyone really see's whats happening.
Good luck to you.