Vagabond, thanks for your mostly? thoughtful post. I'm just going to make one general reply, since I don't know how much time, if any, I will have to revisit this thread since not many other people shared their own personal stories.
The last actions I took in life with this woman were:
1. cuddling on the couch with her, watching a movie, her wanting me to kiss her, and me turning her down because she was still in a long-distance relationship (she broke up with him a few months later anyway, presumably to date someone local who did kiss her when she offered him the chance)
2. she asked me out to dinner the last night we saw each other. it was a pleasant evening, as always, and i walked her back to her place and politely said goodnight
3. we were no longer next-door neighbors, but then i moved again, this time to another state, and when i was settled, thinking we were just lifelong friends at that point, i tried to catch up with her and see how she was doing. it could have been a few weeks or a few months since the last time we spoke/saw each other, i don't remember, but she did not return my call and blocked me. perhaps because i did something to anger her before i moved, perhaps because i moved suddenly without telling her, or perhaps because she waited around on me for two years and when i moved away, she was only interested in a romantic relationship, and saw no further point after that
4. i was absolutely devastated by this broken bond in life. nevertheless, i have not contacted her or attempted to see her in 17 years
Somehow out of all that, I was compared to, or accused of being, a rapist, a stalker, a misogynist, a potentially abusive partner, crazy, and in need of a restraining order, by various people in this thread. Needless to say, those posts were all projection and perhaps it's those people who are in need of therapy themselves.
On the other hand, some other users did bring up valid points, about it being too late, it's in the past buddy, time to move on, or maybe i'm just fantasizing about what could have been, or maybe because she's in a marriage with children it would be a horrible thing to try and pursue her again. Conversely, I'm surprised at least one other person didn't say go for it, considering studies show AT LEAST 20% of all married women and 40% of all married men ADMIT to having extramarital affairs, and something like 50% of all marriages end in divorce. There certainly are a lot of shy FSU users reading and posting in this thread.
But when I started the thread, my intention was to see if there were other stories about people who had a similar experience, or maybe the greatest love of their life had passed on from an accident, disease, old age, somehow they had become separated for whatever reason and they just accepted it or never really accepted it, stayed alone or moved on with someone else. Obviously that was a miscalculation, but thanks to those of you who did reply!