Sure, they also list redshirts as an ‘unbuilt trope’
Live-Action TV / Unbuilt Trope - TV Tropes
Then add all the episodes (and movies) where he runs into a former lover. We only see snippets of his life after he became a Starship Captain and married to the ship. Imagine how much of a horn-Horta he was in high school, or at the Academy. Or as a junior officer.
Memory Alpha lists four different women with whom Kirk had relationships when he was younger, prior to them appearing in an episode or movie, plus all of the ones which he kissed or flirted with in an episode:
- Ruth (Shore Leave)
- Janice Lester (Turnabout Intruder)
- Carol Marcus (The Wrath of Khan)
- Janet Wallace (The Deadly Years)
Plus, Helen Noel (Dagger of the Mind), with whom he’d had a flirtation at a Christmas party on board the Enterprise, prior to that episode.
That we know of. 
And you know that Kirk banged the boots off the Ruth simulacrum off-screen in “Shore Leave.”
You now have me wondering which episode from the original run is the most, uh, typical? Or clichéd? Or possibly: trope-tastic?
(Top of my head, maybe it’s BY ANY OTHER NAME: Kirk makes out with an alien lady, and punches out an alien dude; and Spock does the Vulcan mind-probe, and talks about what’s logical while playing 3-D chess; and Scotty pulls off an on-the-fly engineering feat, and in his Scottish-themed quarters drinks the foe du jour under the table; and that’s all after the redshirts drop like flies to show us how serious this all is, plus we get to see McCoy do some doctorin’ in sick bay…)
The list is off by at least one: Ariel Shaw in Court Martial
Kirk: It’s been… How long has it been?
Shaw: Four years, seven months and an odd number of days. Not that I’m counting.
Yup, you’re right, I accidentally skipped Areel, while reading through the (very long) list of Kirk’s romances. So, five (known) former lovers.
Then they breach the energy barrier at the edge of the galaxy. Again. They avert the “Black Guy Dies First” trope.
They forget “that little blonde lab technician” Mitchell ribs Kirk about. “I almost married her!”
Though I have fankwanked that this unnamed woman is none other than Carol Marcus. but I’ve never seen anyone else say that.
And honestly, I don’t get this “Ruth” infatuation. She acts as exciting as a potted plant. They don’t even give her any lines!
I imagine Kirk likes exciting women, like Dr Marcus, not vapid eye candy like Ruth.
He was young. She was easy. 'nuff said.
I thought that was the trope, that he’d make out with Space Babe of the Week in order to get something he wanted (something else that he wanted) then cast them aside and beam back up to the ship.
I wonder how Kirk’s tally of 19 compares stacks up against the other men on the series, both regulars and guest stars. Spock, Bones, Scotty, Chekov, Captain Pike, Gary Mitchell, Zefram Cochrane; how many others had some degree of romance, or at least flirtation, over the course of the series?
Total sidebar:
Joan “Areel Shaw” Marshall was the original Lily (as “Phoebe”) in the original pilot of The Munsters.
IIRC Spock, Scotty, McCoy, & Chekov all had 1 romance episode over the course of TOS. Not counting Chekov’s drill thrall.
I thought part of the problem was that the networks didn’t want Star Trek to be a vehicle for one of Gene’s mistresses.
It was really convenient for the crew that every single planet they visited was so ideally earth-like that they could beam down without even a windbreaker.
Except for the one that tried to kill Sulu (“The Enemy Within”). And the one where the crewman got the water virus (“Amok Time”), and the one where…
Of course most of the places they stopped were Earth-like. What the heck are they going to do on the analog of Neptune?
That’s the one where they forgot how to beam down blankets.
They could, but they might end up being evil blankets, all itchy and stuff.
But the other blankets would be soft and cuddly.
Can’t take that chance. The landing party will just have to chill until the transporter is fixed.