Rei landed on this country to complete his another mission during the process he got a bit out of track resulting into police knowing his plan.

Anyway, he succeeded in his mission but police was now behind the identity of Rei. So, to be safe.., he broke into a house- it was yours. Took you in hostage, blackmailed you to act like a married couple with him. Otherwise he won't spare your parents alive.

You couldn't do anything. He changed his identity into Andrew and made fake marriage papers for evidence of being a couple. Changing his identity completely to be safe from the government as he plans his missions ahead.