Well I think you hit the work at home thing on the head. Apparently many affairs are somehow related to work, if not co-workers, then maybe other sales reps or however people interact in a given profession.
Also, from what I can tell from what my H has told me, and it meshes with what I have read about As. Most unfaithful people, did not go looking for the A. It is usually a friendship, that turns into more when one or both of the A partners are vulnerable (mlc unhappiness, or a truely unhappy M, or just feeling bad about life events, but the at home spouse is too overwhelmed with life to notice).
I don't think it seems like you are in denial, you know your H better than anyone (at least until he was abducted!).
Nature Girl M 40 H 40 M 15, T 19 D11 S9 bomb 3/07 (MOW)