I was thinking about Babylon 5 and noticed something odd and perhaps unintended by JMS: excluding the too-alien characters like the Vorlons and Shadows, every major character on the show had at least one romance subplot, except for all the Narn characters. We know that Narns do have romance, marry, and mate (from G'Kar's stories of his family), but none of the Narn characters ever show the slightest inclination towards romance or even refer to it in their past. (G'Kar shows plenty of inclination towards sex, but it's clear it's not romantic at all.)
For these purposes, my definition of "major character" is anyone we get to know well enough that we'd know if they had romance in their lives. Anyone who was in the credits counts, and a few that weren't might still count. Let's go through the roster.
- Sinclair: His relationship with Catherine Sakai runs through all of season one, culminating in an engagement.
- Sheridan: In addition to his backstory with Anna, his arc with Delenn is a central plot throughout the series. (His marriage with Lochley is mentioned but never discussed in any terms that'd make clear it's romantic in nature.)
- Ivanova: Unlucky in love, she had a few subplots with a Home Guard fellow and a comedy of errors with Lieutenant Corwin, but her big romance stories were with Talia and Marcus.
- Lochley: Since I'm not going to count her dates with Gideon in Crusade she almost manages to be the exception, but it's clear her relationship with Zoe (revealed when she meets her ghost) was clearly romantic in nature. (I could probably also count Sheridan, but as mentioned, we never know if there was any romance in that.)
- Garibaldi: Despite his long-term campaign of badinage with Talia and a few encounters with Dodger, Garibaldi always found his way back to Lise.
- Zack Allen: Poor timing ruined his ongoing infatuation with Lyta. (And he's so dumb it never occurred to him later to reconsider that encounter in light of what he eventually found out was going on.)
- Warren Keffer: Despite being in the credits a whole season he really shouldn't count as a major character. But even he has a throwaway scene introducing his love interest back home.
- Marcus: His tragic romance for Ivanova runs through two seasons.
- Talia: One could argue nothing Talia did counted since it was all really the PsiCorps construct, but really, that construct is who we knew as Talia. And she had backstory romances with Matt Stoner (okay, not really a romance) and Jason Ironheart (definitely a romance), as well as her pillow-talk romance with Ivanova.
- Lyta: Lyta was oblivious to Zack, but unfortunately (for us as much as for her), did not resist the charms of Byron.
- Byron: Please don't make me remember.
- Bester: Not really a major character, but even so, he managed to have not only a wife and children back home (though that might have been a lie) but a romantic interest in a telepath-cyborg-popsicle that became a plot point.
- Delenn: See Sheridan above.
- Lennier: His unrequited love for Delenn becomes a plot point through the final season.
- Londo: While his relationship with his three wives clearly doesn't count as romance, his passion for Adira Tyree lasts through the whole series despite her only appearing in two episodes (plus a body bag in a third).
- Vir: Almost the exception, but he did clearly have moon eyes for Lyndisty for most of an episode there.
And yet, for as much as we see G'Kar go through many changes over his life, and while we see him express a sexual interest in human females, there's never a moment where there's even a hint he has the slighest inclination to romance, or any history of it. Na'Toth's history gets cut short due to losing the actress, and she spends quite a few years in prison, but what we see of her makes the idea of her being romantic seem alien, and there's no sign of it. Ta'Lon doesn't even indicate any romantic tendencies (though he's hardly a major character). I don't even recall any other storylines in which even single-episode Narns have romances, or any suggestion of romance beyond the mere fact that they have families.
I wonder if JMS did that on purpose.