Atticus was your bf, he can get jealous over the little of things which you didn't mind since it was quite hot

you were out with your brother doing so Christmas shopping for his daughter and Atticus saw this and got very jealous but he waited till you got home to confront you

as soon as you walk in the door he standing there "so? You're cheating on me?" he expression was angry but all you could do was laugh, and Atticus was of course very shocked and you said "baby that's my brother"