La-da-da, la-da-da, la-da-da-da La-da-da, la-da-da, la-da-da-da How did we get here? You showed up so low, but I know she's at home And you're acting so sincere, sincere, sincere I was thinking about leaving Making up a lie, but had to say goodbye To stop your boy from cheating, cheating Stop your boy from cheating, cheating Stop pretending she's not sending Fear straight to your phone It's so tempting, no good ending With you and me alone Tonight I'm kissing my ex-best friend's ex-boyfriend The ex-boyfriend Tonight you'll both be saying my name like I'm to blame And it's a shame, I-I-I'm not sorry Won't stop me tonight I'm kissing my ex-best friend's ex-boyfriend The ex-boyfriend La-da-da, la-da-da, la-da-da-da La-da-da, la-da-da, la-da-da-da La-da-da, la-da-da, la-da-da-da La-da-da Wasn't thinking how she'd feel Should've known she'd be pissed when she heard that we kissed But you said, what's the big deal? Big deal, you know that you're the worst thing I could steal How'd I do this to my best friend? Cause it's not my style to fall for a smile But we're gonna make a mistake, mistake Gonna see her heart break, heart break Stop pretending she's not sending Fear straight to your phone It's so tempting, no good ending With you and me alone Tonight I'm kissing my ex-best friend's ex-boyfriend The ex-boyfriend Tonight you'll both be saying my name like I'm to blame And it's a shame, it's an ex-mo I'm not sorry, her attacks won't Won't stop me tonight I'm kissing my ex-best friend's ex-boyfriend Ex-boyfriend La-da-da, la-da-da, la-da-da-da La-da-da, la-da-da, la-da-da-da La-da-da, la-da-da, la-da-da-da La-da-da Someone's gonna get jealous Someone's gonna get hurt Someone's gonna get lucky But it's not gonna be her tonight I'm kissing my ex-best friend's ex-boyfriend The ex-boyfriend Tonight you'll both be saying my name like I'm to blame And it's a shame, it's an ex-mo I'm not sorry, her attacks won't Won't stop me tonight I'm kissing my ex-best friend's ex-boyfriend Ex-boyfriend La-da-da, la-da-da, la-da-da-da La-da-da, la-da-da, la-da-da-da La-da-da, la-da-da, la-da-da-da And I'm to blame La-da-da, la-da-da, la-da-da-da I'm not sorry, her attacks won't Won't stop me tonight I'm kissing my ex-best friend's ex-boyfriend Ex-boyfriend