Lyric discussion by IfUSeekAmy 

Cover art for How Can I lyrics by Charli XCX

The song lyrics don't really state what she had done to make her, "fuck up" the relationship.

All we know is that she's done something bad to draw their relationship to an end, presumably adultery? "Can't blame this one on bad luck."

Anyway it's pretty clear the song is about her singing how she's done something to cause their relationship to end.. and she's asking, "How can I fix, what I fucked up?"

Song Meaning