He starts hitting on you as soon as he becomes a companion and that's it.
So im not the only one who finds it weird.

Sometimes it feels like one day someone enters Swens office ... and the scene was something like this:
Developer: "Hey boss, Twitter shows that people really likes this NPC."
Swen: "Uh-huh ... make it fuckable."
Developer: "Uh-huh ... and?"
Swen: "What do you mean, and? Thats it."