Maybe Arthur doesn't suspect enough of strangers.

You looked like a sweetheart when you first met. Dreamy, kind of anxious and bad with words, saying things to please him. He's not stupid, but sometimes he also sees kindness in people who he shouldn't. He should, much less, be romantically involved with people like that.

Now, with you at your ranch house, Arthur realizes. You are insane. Dreaming of running away with him, showing all the strange crazes you have. He's better leave before it's too late. He slowly backs up, and that seems to break your heart.

'did i do something wrong?', you question, confused, saddened. And he don't know how to answer.