This guy I had a huge crush on in junior high tracked me down when I was in my 20s. I was thrilled at first, then learned he had turned into kind of a cultish religious nut. Instant turnoff.
Then there’s my first true love from my early 20s. I can’t remember why exactly we broke up but we stayed in touch and even hooked up again some years later. Then we both got married and eventually lost touch. He reached out to me again recently, and I was hit by that same old feeling. But I realize it’s like what you said, it’s a feeling I once had. People change over the years – I sure have – and I know almost nothing about him now. Plus we’re both still married. Still flattering for me though.