[Verse]
If I told you how much I think about her
You'd think I was in love
And if you knew how much I looked at her pictures
You would think we're best friends

[Pre-Chorus]
'Cause I know her star sign, I know her blood type
I've seen every movie she's been in, and, oh, God, she's beautiful
And I know you loved her, and I know I'm butthurt
But I can't help it, no, I can't help it

[Chorus]
I'm so obsessed with your ex (Uh-huh)
I know she's been asleep on my side of your bed, and I can feel it
I'm starin' at her like I wanna get hurt
And I remember every detail you have ever told me, so be careful, baby

[Post-Chorus]
I'm so obsessed with your ex (Ah)
Yeah, I'm so obsessed with your ex (Ah)
I'm so obsessed with your ex (Ah)
Yeah, I'm so obsessed with your ex (Ah)
La, da-da-da, da-da-da
La, da-da-da, da-da-da