I swear I feel she dedicated this to Xiah Junsu..when on one radio show she talked about her first love ( that happened apparently in 2oo8. when also she and Xiah were dating) she said she is really sorry that she acted with such pride and could not get pass some situations,basically Xiah is her biggest love,and she never got over him.
They were too young and in this industry that forbids dating,and they were caught,so..yeah.
I will also never get over TaeSu,and I miss them so much.I miss them and I miss my OT9 and OT5:)
I feel she is with Baek just because he reminds her of Junsu ( especially singing part)
This is her true emotions ,all poured in this song
Love Taeyeon