Thoughts During an Unexpected One-Night Stand...

I've been married for three years now, but last night I did something that felt like a departure from our routine. After a long day at the campus library studying, I found myself chatting with this guy in another lane of cubicles. He seemed genuinely interested in my work and our conversation led to drinks later. Before we knew it...we were back at his place. It was consensual and clear that there would be no strings attached. But as I lay there thinking about what just happened, I couldn't help but wonder if this means anything more than a momentary lapse of judgment. Any thoughts on why someone might slip up like this even when they have a happy marriage?...