Only a stupid Person wouldnt understand this song. Its about trying to forget your ex while dateing someone knew. But you can't. And so you have to leave the new person because Your not over your ex and you keep on thinking about Him/her and all the memories. They wont go away so you have to leave the new person your dateing Because you can never treat them the way you wish you could because of your ex. And it is only unfair to the new person So you have no choice but to leave. Unless You Come across of case of Amnesia So you wont remeber anything about your past.