I think this song is about the narrator realising that it is not good for him so keep seeing a certain girl. Sometimes people get too attached to someone and it gets to a point where its not healthy, where the only thing that person cares about is the other person, "you said you would die for me". The price the narrator has to pay is realising it is not healthy for him to remain being with the girl he loves. Seeing as shes very attached to him she is most likely not going to take it very well, so in a way she must go on living for him.
I think this song is about the narrator realising that it is not good for him so keep seeing a certain girl. Sometimes people get too attached to someone and it gets to a point where its not healthy, where the only thing that person cares about is the other person, "you said you would die for me". The price the narrator has to pay is realising it is not healthy for him to remain being with the girl he loves. Seeing as shes very attached to him she is most likely not going to take it very well, so in a way she must go on living for him.