I don't think they were together like that! to me it seemed more like they were work colleagues or something of the like.
G (the doctor/scientist dude) and the pig guy were in the first chapter together! G was beating up (?) the pig guy, so i think they must've come from the center together to check on the human livestock, and they have some kind of abusive power dynamic. Seems like the pig guy IS interested/in love with G tho... at least thats what I was getting from the end of chapter 15... I think they have some kind of friends with benefits dynamic too.
But they teased the pig guy in a few different chapters! And since the author said little A isn't strictly a top, they must be introducing new characters later down the line to add to little A's harem, so the pig guy makes a reasonable option! Female pigs have heat cycles too, so maybe that will come into play

Idk but for some reason I want little a to become a bottom at some point to or a switch?