Changmin had this special way with girls. Well, having 5 older sisters would do that to a guy. 5 different, not to mention difficult, personalities had prepared him to deal with all sorts of girls. Love advice? He's the guy. Need a recipe to charm a heart? Go to Shim Changmin. Fashion advice? Shim Changmin to the rescue. 

Great guy wasn't he? Girls flocking to him was like another norm in his life and so, who would have thought that his love life is practically barren of any excitement. The fact that he's got the hots for a guy and not just any guy but the most annoying, charismatic, beautiful, out-of-his-league guy, did not help any. 

In short, Changmin's doomed to live a lonely, sad, single life. 

...probably.