First of all, there's nothing wrong with you.
I have had a similar realization to integritymatters.
I know this is super trite, but I've been thinking a lot about the serenity prayer, and it's given me great comfort. (Grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to tell the difference.)
Applied to my particular situation (my WH is similarly wonderful though my dday is much more recent than yours), I think that if my WH is going to cheat again, he's going to cheat again. No amount of worrying about it, checking through his email accounts, obsessing about where he is and what he's doing, wondering if I can trust him, telling him to be honest, thinking about how devastated I would be if this happened again or how completely it would ruin my life, worrying that if it happens again later I'll be too old to find another partner, whereas if I just cut and run now I might have a chance, or tearing myself up about anything else is going to make a difference.
I can't control what he will do in the future. And you can't control your WS.
All I can do is try to recognize that no amount of worrying ever changed the outcome of anything, that the only thing I can do to help prevent a recurrence is to work on being the best, most healthy, strongest person I can, to put my effort and love into our marriage and into myself, and to be mindful of the now. This is, of course, way, way easier said than done, and I don't always succeed, but thinking about it often helps me move on from whatever I'm worrying about at that moment.
If he does do it again, that truth will come out. It *will* come out. Buried ugliness has a way of doing that. And you can deal with that if and when it happens. You can, as integritymatters said, deal with it much better if you've spent the intervening time cultivating inner serenity.
I'm not usually so hippy-dippy, and someone's probably already posted this a hundred times, but:
“Worry never robs tomorrow of its sorrow. It only saps today of its joy.” -Leo Buscaglia
I'm not trying to sound like an obnoxious quasi-guru. I'm absolutely not always able to embody all this stuff myself, but trying to think this way has helped pull me through a few rough spots so far.