So sorry for your sitch. I am in a similar position. D is near. We have not yet filed (expect to do so ourselves - no young kids, house sold, no maintenance - just simple division of debt and financial assets), but expect to do so soon.
I notice that I have been waking up at 2 am almost every night since she called a week ago (after 6 weeks nc) and after a 40 minute conversation catching up she indicated that we should file soon. This whole thing is surreal to me.
The OM can not be that devout a catholic if he is pursuing a married woman. As a catholic, that is just my opinion. Also, keep in mind that, according to numerous sources, marriage to the affair partner typically ends in divorce 75-85% of the time, versus the normal 60% for second marriages.
Me: 48 Ex-W: 45 M: Nov '96, together since Oct 93 Bomb: on 10-yr anni - Nov '06 OM Separated: mid-Feb '07 Divorced mid-July '08 One daughter - 28 XW living w/OM