Caught In The Moment

I'm in my late 20s and married to my high school sweetheart. We've been together since I was eighteen, so there's this deep history that ties us together despite our different tastes and interests as we've aged. Last month, I attended a friend’s bachelor party, which had a wild reputation. I hadn't planned on drinking much or even staying late, but I ended up with far more alcohol than I meant to. During the after-party at my apartment (because why not have one?), there was this bartender I'd struck up a conversation with earlier in the night. We exchanged numbers and, well, you know how it goes, late-night chats, laughter over drinks that turned into something more. It wasn't until hours later when everything had cleared up did we realize what happened. The next morning, as we were leaving, she hugged me goodbye and whispered about us being adults who make choices, not just kids in a drunken haze. I'm trying to sort this out, am I the asshole for letting my guard down, or is it normal to feel a spark of something more when you're around someone with a different vibe than your longtime partner?