Luffy ending up with anyone I think kind've ruins the point. A man's romance is the adventure, that's all that's ever been prioritized.
I do disagree that Luffy is asexual. WOG from Oda himself mentions that Nami's happiness punch>Hancock's Mero Mero no Mi which is why Luffy was affected (also something about playing up his horniness because he was having a "boys moment" with his bros or something idk so we know that Luffy does find women attractive it's just not played up nearly as much as any other character because the thrill of the adventure is what his mind is focused on (and pirate king and fighting and meat)