Oh, sweetie, my H didn't even have an actual A, just was writing love letters he was planning to send to another woman and hung out with her as a "friend," and I still have moments now two years later. I know he's way over and done with her, but it did a number on me big time.
My aunt's husband cheated on her nearly 30 years ago, and she says there are still times she wonders. My uncle still calls her if he's going to be even 5-minutes later than he said...it's part of the transparency they agreed upon long ago.
Six months is not a lot of time. You were just trying to survive, right? And now you are processing those feelings, the idea that marriage really isn't foolproof.
Are you guys in MC? If not, see if you can go. Not to rehash the past to death, but to help process your feelings and set new norms and behaviors for your marriage.
Do I feel secure? I'd say 98%.
Be patient. It's going to take time to heal and for your H to prove through his actions that it's really over.
SD
Me: 40 H: 43 H had EA from 2/06-9/06 Bomb 5/06 Piecing since 9/2006 3/2008: Boundary setting 7/2009: Boundary crossing~dropped my own bomb. 8/2010: Marriage finally on track!