Because in every dark side, there is always another darker corner and Kang Daniel just got trapped inside one. Because just like any other human, he is doing whatever it takes to survive.

Frankly, paying for online dating sites is not half as bad as being married to someone else, but in Kang Daniel's case, he just have to deal with both. 

Kang Daniel is a puppy-like bartender that buys you drinks because he said you are too pretty to be sad, and oh, Ong Sungwoo kind of a help in this case.