What is a SONG that reminds you of a past Love/Fling/Hookup about which your current partner has no idea?

Tonight while driving home, "Maggie May" by Rod Stewart came on the radio and it reminded me of a coworker with whom I had a sort of 'Pam and Jim from The Office' kind of thing. There was an apparent chemistry between us even though she had a boyfriend who under-appreciated her tremendously. Eventually our attraction led her to break up with him because she realized that she would be happier with me and we ended up spending a great night together. Naturally I was ecstatic after hearing this news and I couldn't believe that my daydreams of imagining what it would be like to be with this girl would actually come true.

Then a few days later I went to see her and she became awkwardly distant. She then told me that she got back with her boyfriend for reasons that I still don't quite understand to this day. As you might imagine, I was not only devastated but I felt especially used. She's a great girl, and I know she wasn't out to break my heart, but in my solemn despair, I needed to let her know how much she hurt me and so I was going to give her a copy of "Maggy May" burned on a CD and tell her that the song would explain everything. I never did because I after my initial pity party I moved on to anger and I purposefully "lost touch" with her.

Don't get me wrong. It's not like I'm hiding a secret love for this girl - they're just memories that got tied psychologically to that song. In fact, I entered a relationship of 3 years right after that 'fiasco' and now I'm in another going strong. However, each time that song comes on, it never fails to make me remember a la Pavlov.

TL;DR: Co-worker and I develop feelings for one another. She dumps her un-attentive boyfriend for me, we hook up briefly, she then tells me that she wants to get back with her inconsiderate boyfriend. Rod Stewart's "Maggie May" encapsulates this experience for me.