In the first verse, the singer has gotten his heart broken and is very depressed. Then the girl who dumped him wants him back and he tells her that its too late, he has lost her trust and can't go back and undo the pain she caused, so she should leave you alone.
The chorus is about remembering the relationship and just wanting to let the person who dumped him know that he is getting over being dumped but not getting over her.
In the second verse, he still wants to talk to her even though he knows that he can't let anyone see his emotional pain and has to hide it. He also wants her to realize that he is gone for good and it's all her fault.
After that, he is slowly realizing that she is also in pain and that the whole break up really wasn't her fault, but he still can't trust her and fix the relationship so he is asking her to forget the relationship they had. He still cares about her, but knows it can't work.
Tiffany - Somerset, PA