DCB,

Consider this...if you get focused on if there's an OW and there isn't, you will have lost time toward making those changes about yourself. If there was an OM, and it seems you have no evidence to suggest that, then why would that be? It would be because of a failure in the relationship - the connection that cemented you together for many years slowly or suddenly dissolved.

Keep your eyes open, but focus on the target - a happy marriage.