I have been typing in random key words for ages into Google, but I just can't think of the name of this song.

It's a dance song.
In the video there's a band playing, and there's a chinese girl dressed as a schoolgirl dancing in the background (sounds weird but its actully quite tasteful) and at the end of the video, the lead singer of the band, the girl, gives the guy who was watching them play photos of him cheating...

I can barely remember a few lyrics, but eveytime I try to formulate them, they're gone...

If the singer was blonde then you might want to look up Gwen Seffani songs on you tube or something and see if there is a match there. She often has her friend (chinese girl) in her videos.