Thank you all so much for your comments and input; I really appreciate it! I guess I need to remember the line between the healthy sharing of information, even if some of it is emotional, and the unhealthy (for the kids) venting about petty things like whether he is bad-mouthing me. It's just that sometimes the stress and rage just overwhelm me.
I have been slowly building up some social support groups. We've moved a lot (like six times in the last 12 years), so it's been hard to maintain a consistent social network. But now I'm in a Christian book study group, and I go to Al-Anon, and I'm in individual as well as group therapy. And, of course, the kind people here at PC.
I totally agree with you all that I must stay away from Facebook, since that is a huge trigger for me. I myself am not a member, but I do scan my daughters' pages about once a week to make sure nothing inappropriate is there. I need to leave it at that and just check quickly and log off.
Cutebagaddict, I had to laugh at your comment
"Your husband needs to be confronted, he can't make a drastic comment about divorce to you, then not have the balls to deal with the aftermath" because that is EXACTLY how I feel!

I am actualllyquite furious with him, but I am NOT going to make this easier for him. I do not want a divorce -- I think we have a good chance of working things out -- so if he wants to file, then he needs to file.
Thank you again. You all have given me some food for thought, as well as kind support, which I genuinely appreciate -- more than I can adequately express.