At this point he should of said Let me get your number to the girl, since Lee yeon is acting like she is ashamed to say he is her husband.. If she doesnt want to raise supisions in Chae Woo, then she needs to be more convincing. They have been married for 2 years, she should be more than used to telling people he is her husband. He is already questioning a lot of things, he isnt dumb, eventually he's going to catch on.