Hello, 
Wonderingwhatwentwrong. Welcome. 
Says it was "only"
Anyone busted for anything will typically go straight into "damage control" mode. Wayward spouses will minimize what happened, trying to convince themselves, and their betrayed spouses, that "it wasn't that bad." It's natural, unfortunately.
The Healing Library, accessible from the pull-down menu at the top of the page, has an "Articles" section full of tremendously helpful essays written by veteran members. There are a couple of essays about getting at the truth. 
I guess my question is… does it ever work after?
Yes, it does. Reconciliation is possible. It's a very long journey and extremely challenging.
It really is out of character,
Most of think so, too, at first. Part of that is just the shock of it all. It's sooo hard to accept that our spouses were capable of doing whatever it was that they did.
Being able to have an affair is, as demonstrated, a part of your WH's character. At some point, you'll most likely demand answers to why that's true. And while no reasons will ever justify infidelity, understanding why your WS chose to betray himself, his family and jeopardize his career, is critical to rebuilding trust. 
I believe that infidelity is self-destructive. Sometimes people simply break. They blow-up their own lives and we, the betrayed, are collateral damage. 
His affair had nothing to do with you. Nothing you ever did or didn't do, nothing you ever said or didn't say, would have made any difference. Good marriage and bad have nothing to do with it. Prettier, thinner and younger had nothing to do with it.
His affair had everything to do with himself. His inability to deal with whatever issues he struggles with is what lead him down Infidelity Lane.
 [This message edited by Unhinged at 4:26 PM, Sunday, November 2nd]