I really think that the romances are just unfinished, which is also why they feel so sudden.
Probably for the same reason why Larian gave us so many '' evil '' companions, they're testing things out.
It kinda makes sense to have something a bit different then to see how people will react to it too.
Or they took "pick me" route. Choice like in one of Deux Ex games, press 'button' of your choice.
