Meli, You sound like you have your head and your expectations right where they need to be. It is common for the LBS to have feelings of inadequacy. No one is perfect in all aspects of their marriage at all times. We all could have done better at this or that. We all have our faults and weaknesses. We have all said the wrong thing at the wrong time.
Whatever your H was looking for in the OW, it was not your fault that he started his EA. That is his character flaw, not yours. Don't become overly negative on yourself for his faults and failures. Keeping that in mind will help you detach and focus on what you can control: you and your kids.
I am curious about some details of your sitch, though. I have recently become suspicious that my W might be bi-polar. Did your H have any tell-tale symptoms that might have been a warning to you about his condition, prior to the diagnosis?
Me40 WAW37 M18 T20 S18,14 D13 EA Bomb 6/08 Sep 11/20/08 Ret 08/09 Sep/Filed 11/09