ShesGreat - I'm glad you posted this thread. I have made up my mind to believe my H when he insists (and now makes a joke out of my questioning) that there's no OW for the same reason many people here have said - it just doesn't do me any good to focus on the what-if. I'm healthier for looking at me and moving along, and I figure if there has been an OW not being exposed (! ) now, we will deal with that later if we need to. As for how I would deal with that, I don't know. I guess it would matter how the whole thing happened and where H&me are and what we are trying to do... so too complicated again to worry about today!
I say I'm glad you posted this thread, though, b/c when I was thinking this topic through earlier in our separation, I had many people here on DB.com suggest any disbelief in an OW was naive. The posters on this thread, though, lead me to believe that, naive or not, I'm in good company to just not focus on the question.
Hope all of the responses help you with your own sitch.