In this thread Harry Chapin’s song Taxi was mentioned and Dan Fogelberg’s Same Old Lang Syne were mentioned. What are others with the same story. Mary Hopkin’s Those Were the Days sorta fits. Any others?
“Martha”, by Tom Waits may qualify. It’s about a man who calls up an old flame, looking for her on the off chance that she is still at that number.
It’s a staple in our house, since that’s exactly what my stepdad to reconnect with my mom after their marriages (to other people) broke up. They had been just friends way back when, married their respective sweeties, and then moved to different citioes, and he never forgot her. He dialed her up randomly one day and now they’ve been together for more than a decade. Also, my mom’s name is Martha.
Van Morrison “Brown Eyed Girl” has a mention along the theme in the last verse, and the rest is largely reminiscent.
Little Texas’s “What Might Have Been” and Garth Brooks’s “Unanswered Prayers” are both good examples of this type of song.
Streisand’s “The Way We Were”
David Hollister’s “One Woman Man.” Opening lines: It’s so funny running into you/ It has be three years/ Since we last seen each other/ Many flashbacks come to mind/ All the wild and crazy times/ We used to have one another…
The song veers off into David singing about how he’s so in love with the woman he’s with now, less so about the meeting.
Paul Simon, “Still Crazy After All These Years”
Dan Fogelberg, Same Old Lang Syne.
That Was a River by Collin Raye sort of fits.
I’ve seen that look before
Here comes that doubt again
You think that girl we saw
Was more than just a friend
Yes, there was a time
I thought she had it all
She meant the world to me
Back when the world was small
[…]
I’ve been getting nostalgic for the country I used to listen to recently. I really need to hunt down some 90’s love ballads.
I suspect you are guilty of something I do all the time - only reading part of the post.
I mentioned Same Old Lang Syne in my original post…
Roxy Music: “Chance Meeting”
Donovan: “Hi It’s Been a Long Time”
Isn’t Life Strange Moody Blues
Desert Moon by Dennis DeYoung (formerly of Styx)
Does Night Moves by Bob Seger count? It’s just a guy remembering an old love, though, I think.
The same is likely true of Paul Davis’ '65 Love Affair.
Dating myself? Whatever do you mean? 
Oh, and I originally came into this thread with the intent to offer that one. Rats. 
I’m surprised nobody’s mentioned Bob Dylan’s “Tangled Up In Blue”.
Roy Orbison’s Crying (best version imo: his duet with k.d. lang)
What’s the song that begins with a line to the effect of “Saw my ex lover in the grocery store”?
Remember Walk On By sung byAretha Franklin? It’s one of my faves!
The first one that popped into my head was “Ain’t It Funny How Time Slips Away,” by Willie Nelson.
*Well, hello there
My, it’s been a long, long time
How am I doing?
Oh, I guess that I’m doing fine
It’s been so long now,
But it seems now, that it was only yesterday
Gee, ain’t it funny, how time slips away.
How’s your new love?
I hope that he’s doin fine
I heard you told him,
That you’d love him till the end of time
Now, that’s the same thing that you told me
Seems like just the other day
Gee, ain’t it funny, how time slips away.
I gotta go now
I guess I’ll see you around
Don’t know when though
Never know, when I’ll be back in town
But remember, what I tell you
In time your gonna pay
And it’s surprising, how time slips away…*
And this one made me think of Conway Twitty’s Hello Darling.