Jennifer,
When I was at that point in my process I had to remind myself that I was making this decision "for now." I gave myself permission to revisit the decision in 6 months and if I was absolutely sure that I had made a grave mistake then I could always approach my exH and ask to reconcile.
I never did, but giving myself the "for now" option helped me to remember that I have choices. Oh, and another thing, I was later involved with an incredibly active alcoholic (a situation that FINALLY motivated me to enter the rooms of Alanon) who swore up, down, and sideways that we could NEVER reconcile if I left the relationship, because that would be IT. But that's the same alcoholic that still pops up every now and again, even though I've gone no contact.
Actions speak louder than words...he's telling you everything you need to know, for today.
One day at a time,
posie