@epicwalrus ok here we go this is gonna not be cohesive at all but we're going for it anyway!! This is also all from memory so anybody please feel free to correct anything I get wrong.
Quincy is the only person in the game who has been stated to canonically have had a past romantic relationship outside of the clan, and it shows.
That's not to say nobody else has ever had a partner. Eiden, Rei and probably Kuya have definitely had sex with multiple people before the events of the game, plus we know Aster and Morvay get with each other. But Quincy is the only person where they've gone out of their way to explicitly mention that he had an "old lover". Eiden might have exes, Rei could too, but given both of their initial attitudes towards being given that sort of affection (Eiden constantly being surprised, Rei not seeing the value in it), it's probably safe to assume any relationships they could have had weren't long-term.
It makes sense, when you think about it. Quincy's whole character revolves around his experience outliving his closest bonds and being outcast from his tribe because he doesn't age. Nobody else went through this - Kuya and Blade didn't seem to be close to anyone other than Huey, Rei chose to sever all ties with his old life himself, Aster and Morvay are each other's closest bonds and everyone else is still young. So if anyone was to have a past lover, Quincy's the most obvious choice, because that's another beloved person for him to lose.
What's interesting, though, is how the writers chose to approach it. Quincy's old lover is very rarely mentioned, and never actually described. In fact, if you don't read Quincy's intimacy rooms, you'd have no idea he had an old lover at all. They were mentioned very briefly in Distant Promise Quincy (Astral Duo), when Zaro mentions the order Quincy's friends and family died, and unless I missed something they literally never came up again until now with one flashback scene in Countless Conquests Quincy (Battle of the Gods). It's not even outright stated that that's who it is, but it's the most likely option. Literally all we know about this old lover is that they chose to break things off with Quincy so they both 'wouldn't have to suffer' as they grew further apart in physical age, a move Zaro tried to discourage. Everything about the actual character (name, appearance, gender, etc.) is kept ambiguous so players can imagine whoever they want. Which is a very interesting way to go about it, and one I personally really like.
Because usually in these kinds of games, if a character had a past lover, it's a much bigger deal in the character's lore. Think Heigl with Laica in Noctilucent (which is a hard swing I know but it's the first thing I can think of right now). Having an old lover who passed doesn't need to stop a character from forming a meaningful new relationship in the present, especially since in Quincy's case it's been such a long time. But instead, this old romantic relationship was grouped in with the familial bonds and close friendships Quincy had, because they all meant equally as much to him. That's why it's significant that Zaro is the only name we know from Quincy's past - outliving his friends was just as significant to him as outliving his lover. In fact, the recent scene we got might explain why we know Zaro's name and not his lover's: his lover cut contact, Zaro stayed until he died.
So we don't know much about Quincy's old lover, and they're never really talked about. But that doesn't mean you can't tell this isn't his first time in a romantic relationship. With basically everyone else, it clearly is - in their intimacy rooms (at least early on) there's a certain sense of fluster, of figuring out confusing new feelings, of learning to accept that affection is being offered and that it's okay to want it, and everything that comes with navigating serious romance (or, at the very least, closeness) for the first time. But Quincy isn't learning to love, he doesn't need to; he's learning to love again. His story is about letting yourself enjoy things and make bonds again even if you know it'll all come to an end one day because the memories themselves are worth it. Quincy's development doesn't come from figuring out how to navigate affection, it comes from allowing himself to feel it and act on it once again despite how much losing those bonds hurt him in the past. Once he lets himself act on his feelings, it's very clear he knows what he's doing, both in bed and out of it (picture: the woven crown, that one time he basically praise-bombed Eiden to a colleague, every time he rubs Eiden's head to comfort him which is now something he'll easily do in front of strangers). He may avoid outright saying it (something Topper has no qualms about doing for him lmao) but he rarely hesitates with his actions. And Eiden may surprise him sometimes (*cough* somnophilia *cough*) but the experiences never really seem like a first for Quincy, not like a lot of the others.
I mean, Quincy's the first person in-game that we see kiss Eiden on the mouth! It's literally how his initial H scene starts, and for a game that highlighted the sexual experiences first and started bringing in the actual romance later (another choice that I love btw), it's rather notable that Quincy's one of the only ones that kissed Eiden in their first scene together. Like, this is our introduction to him. There's something to be said about the fact that the man who seems to be the fondest of kissing is the same one who canonically had a past lover.
So yeah. Quincy is the only character that we know for a fact had a past lover and despite the fact that we know barely anything about them, their existence plays quite a big role in setting a lot of his behaviour apart from the others, and I just think it's really cool that we can actually see the difference.
