"You told me everything in your defense
and never understood the consequence"
Meaning, she tried to explain to him why she did what she did, refusing to believe what she did was so wrong, and she didn't understand why he was leaving her, or was mad at her, or was breaking up with her.
"every time's the last time, but I know you'll go and do it again. yeah, you'll do it again."
It's happened before, and he can't take it anymore, he's given her chance after chance, and he's given to her every time, but every time she goes and does the same thing. (Cheats.)
I completely agree with crazymango6,
"You told me everything in your defense and never understood the consequence" Meaning, she tried to explain to him why she did what she did, refusing to believe what she did was so wrong, and she didn't understand why he was leaving her, or was mad at her, or was breaking up with her. "every time's the last time, but I know you'll go and do it again. yeah, you'll do it again." It's happened before, and he can't take it anymore, he's given her chance after chance, and he's given to her every time, but every time she goes and does the same thing. (Cheats.)