Were there ever any unrequited feelings from one party for the other during that period?
Were you or them involved in other relationships during that span of time, and if so, did that lead to any kind of initial anxiety, jealousy or insecurity when you finally got together, assuming that there had been unreturned feelings during that stretch of time?
Well, I knew a girl in High School that wouldn’t give me the time of day.
FF 17 years later, when I ran into her at a bar; she was all about the Shakesman. (We had sex the next day)
Does that count?
Sure, but I was more thinking, you meet someone and know them on a fairly consistent basis over the course of weeks, months, or years before finally getting with them.
Two and a half years.
She knew I wanted her from minute one. Because I told her. Couldn’t help myself.
Her girlfriend knew it too.
We talked every day for that time period, hung out regularly, she introduced me to her friends (she was actually the one who set me up with Happy Scrappy Hero Ex-Girlfriend).
Thirty months later, I was single, she was still with the girlfriend, and her feelings for me just changed.
Boom. It was on.
Lasted six months, we’re still friends to this day.
Met Mr. Matata when we were juniors in high school - 1985. I thought he was a nice guy, but we didn’t really hang around many of the same people. Fast forward to 2009, when we started dating. Married last month.
I met my current wife and fell in love with her almost immediately. She was dating someone else at the time and wasn’t the least bit interested in me in that way. We became best friends and spent most of our time together, and all the while, she never felt “that way” about me. It was nearly a year later that we finally became involved in any “romantic” way, and we wound up married for over 10 years.
One of my good friends had a crush on me for over four years. We were pretty close but I was not attracted to him at all. From the beginning he was pretty much in the neutral box in my head. He would get drunk and pester me about his undying love every so often, but in the meantime he also dated other girls here and there. I finally agreed to a kind of “trial” dating thing in our senior year (university) but it ended pretty quickly - I really just couldn’t summon up any desire for him even though I liked him very much as a person. He took it pretty hard and pretty much immediately went to do his mandatory military service after I told him it wasn’t going to work out. (He had the option of doing the ROTC thing and that had been his original plan until all of this.)
We’re still good friends, but our mutual friends still tease me about how I drove a good man to the army with my wicked womanly ways.
Three months.
Met a guy my second day of chem class. We were pretty attracted to each other, but he didn’t make a move until two months had passed. I was hesitant since he was about to move away and neither of us wanted to get too attached to the other. A month later, on the last day of class, we hooked up in the back seat of his car. Never saw him again. 
(We’re still friends, though.)
I was very good friends with my now-wife for five years before we started dating.
My story is almost identical the Shakes’ - I had an unrequited (and unexpressed) crush on a girl in high school, whom I met at the 20-year reunion. We dated for several years, but ended up parting (we lived 300 miles apart).
I met the future Sr. Olives at freshman orientation of college and I thought, ‘‘huh, he’s kind of a dork.’’ I proceeded to mostly ignore/tolerate him for a few months, even though we shared classes and lived in the same dorm. We ran into one another on a fairly consistent basis and we chatted but not about anything particularly meaningful. I thought he was a little odd, but almost painfully nice. I proceeded to have an on-and-of-again relationship with an absolute nutcase I had also met at freshman orientation.
Then one evening while I was really messed up on pharmaceuticals, he dropped by by dorm room and I proceeded to spill my guts about some Heavy Shit going on in my life. We ended up talking until 4am. I then proceeded to avoid him like the plague for the better part of a year because I was so embarrassed I told him all that stuff. In my head, though, I told myself he was a stalker. Whenever he would drop by my dorm I was extremely uncomfortable and couldn’t get him out of there fast enough.
Then somewhere around the end of the semester, I was in a community performance project that he was required to see for extra credit, and he e-mailed me the following, verbatim:
And I was like, ‘‘Jeez, this guy’s ridiculously good-hearted. I would be a complete tool not to be his friend.’’
So we became immediately joined at the hip, though for several months everything was strictly platonic. We became best friends, and brushed off the knowing winks and nods of others. I think we both had feelings for one another during that time, but they were buried so deep in our psyches they were barely a part of everyday consciousness. We went on dates and everything–we just didn’t call them dates.
We hooked up that summer, in a long and dramatic and thoroughly romantic fashion, and we have been happily together ever since.
Total elapsed time between meeting and hookup: almost exactly one year.
24 years. Reconnected with a girl I knew in college. Just for a wild weekend, but it holds my record for longest time between meet and connect.
Almost ten years. In high school I had a good friend who’s house we’d often hang out at, and he had a very annoying little sister (I think we all see where this is going…) I probably met her when I was 14 or 15, and she was 10 or 11. Several years later I moved back here and started to live with the same friend. His sister dropped by for a party we had and all I could think was,
“Holy DAMN, she got hot!”
She must have thought the same thing about me, cause a couple of months later she had broken up with her current BF and ended up in my bed at another one of our parties. We didn’t have sex right then, but we started to date and eventually did.
I think I’ve got everyone beat. I had an awful crush on this older girl (by 2 1/2 years) from the time I was 7 to the time I was 15, when we stopped summering together. This past year, I formed a Facebook group for all the old summer group to get all nostalgic, she showed up, and we hooked up. That’s a total of 39 years between first spotting her and first getting together with her.
My wife and I knew met though a volunteer organization we both worked for. We knew each other quite well for some eleven years before our first date.
My advanced age is showing–it’s 49 years between the summer I turned 7 and today.
About 3 years.
Neither of us expressed interest in the other during that time, given the situation, which made it completely unrealistic, but once we ended up in the same room together one night it came as no surprise to either of us that we both had been living the same fantasy all along.
About two years, back in college. We were inseparable best friends, did everything together. We had been with the same people but never each other. Over time, I gradually wanted us to become lovers. Finally one night I told him how I felt, and he didn’t take it well at all. He got really upset, said he’d think about it, and left for a few days. When he came back, we did it.
Everyone we knew said, “What the hell took you so long?”
It only lasted a few months. We were much more compatible as best friends than lovers.
Aside from him, my answer would be about an hour. 
Like some others, mine doesn’t exactly qualify because we didn’t keep in touch but…
I met a boy on a BBS when we were 14. We went on one date to an amusement park and never spoke again. I found him a while back, when we were 26, and hooked up for a couple years until we decided we’d be better off as just friends.
I met her at college 29 years ago. I was attracted to her, but she was with someone else, whom she married the day after she graduated. She was divorced about 15 years ago, and I saw her once after that, about ten years ago, but I got the sense she wasn’t interested. (I may have been mistaken about that.)
We recently reconnected and have been dating for about two months.
I wasn’t madly in love with her back then, not even a crush, and I don’t think she was carrying a torch for me, either. But it’s very comfortable having known someone that long, even though we didn’t know each other very well back then.