Just Can't Stop Thinking About It...

It's been a few weeks now...ever since we went to that party with my workmates. There was this one person there...let's just call her Sarah. She’s in her early 30s, I think. We hit it off pretty well...we had some drinks and talked for hours. Then late into the night, when everyone else had gone home...it got a little heated. Nothing really happened between us...at least not that way. But there was definitely an undercurrent of something simmering there. It's just been nagging at me ever since then, wondering what would have transpired if things had gone further that night...if I hadn't kept it all in check. What am I supposed to do about these thoughts? Should I even bring it up with my wife? ...I feel so conflicted.