Hi Shiss. Just read up on your sitch. I am sorry to hear what you are going through.
If H has drawn up papers, you have a choice to make. Do you feel the M should be over? From your posts it seems like you still want to work on it. If so, make sure that at some point you convey that to him. It needs to be done in a calm, and cool sort of way. Make sure you tell him that you have thought about it, this isn't just an emotional or pursuing action, and that it's something you've decided, even after hearing he wants the D. Then be sure to leave it at that. He may insist it's over, not respond, or just be dismissive. If you're ready for that response, you'll be able to deal with it. He'll need time to process that, no matter what.
I guess what I'm trying to describe is detaching. Tell him your intentions without getting wrapped up in an argument. Do it with love and consideration for his feelings, as well as your own. It may well be the hardest thing you ever have to do.
And for what it's worth, you both seem to be reacting as if you really care about one another's feelings. As others have pointed out, you are reacting to one another's negative emotions; it's bad but fixable. If you might want to read up on codependence, and strategies for dealing with it.
Panic is normal at this point, but this is not necessarily the end. You can control how you deal with this.
H: 38 xW: 38 M: 16 T: 18 S: 9 BD: 2/2012 W moved out 4/2012 D: 11/2012