You've been dating him for 2 years and he suddenly moved to Australia. You suddenly lose touch with him and after a few years, he comes back... however, when you meet him he suddenly doesn't know you.

He looked at you with a cold gaze and he then averted his gaze from you. After a few moments of silence he finally spoke up,

"I don't know you...and what brought you here?"

he still stares coldly at your face, there are no signs he remembers that you are still in a relationship with him.