Unmarried Living Together in Seoul?

HI all -
My boyfriend and I are going to be moving to Seoul in the Fall. He will be an English Literature teacher at Seoul Int'l School and I'll be hopefully getting a TEFL placement.

Does anyone know what the general social perception is of unmarried couples living together in Seoul is?

Just want to be prepared as I doubt Seoul is as liberal as the US or Britain..

Thanks for any feedback.
Christina