The Twist Was Unnecessary
So the BF was so distraught after his exhaustive search that he decides to take solace in one of the kidnapped girls?! The logical assumption from that is that he knew his GF was one of the kidnapped and just said Eff it I'll take this Katrina chick. Because clearly if he knew there was a horde of women being sold then he could logically assume his GF was one of them... or better still, actually find out where she was.
I saw no need to make the BF some sex slave addicted creep. It was like they neede to up the intensity and the wow! factor or they just needed another body.