I dunno. I'd say that it's logical, because there's that strong sense of intimacy but...I dunno. I treat all my guy transfriends as bros, you know? I do feel kinda bleak when I realize that my cisgender girlfriend has just never felt this way, whatever qualms she has with her body though.
I have this thing for androgynous women. I swear, when my gf got a haircut my length (a 5 with clippers more or less), I pretty much jizzed in my pants. So in theory I would like early-on transguys as a fetish, but I know the pain too well, I guess. I've found myself completely attracted to transgirls on the other end.
I think, in truth, that transcouples just look awesome to media and whatnot. The world wishes there were more of them--just like lesbian schoolteachers and their students. MOAR