Dido - 'White Flag'
I think this is probably the best song ever written about being in love with someone and having the pain of keeping that person in your life. You know full well that you will run into him again, and you have to pretend you are fine with being "just friends" and have to look like you're going on with your life but inside you are crying. And you can't say anything, because he's with someone else. Having to take the high road, pretending you don't care, never hurt so much.
The best part is the bridge, when Dido sings and her voice goes up with "and you will think...that I've moved on" - heartbreaking.
and when we meet, I'm sure we will
all that was there, will be there still
I'll let it pass, and hold my tongue
and you will think that I've moved on
The interesting bit about this video that I really like is it shows both the man (played by actor David Boreanaz) and the woman as strong, successful people, instead of the woman being just completely desperate and inconsolably sad. This gives me hope.
The part that I find kind of painful is the part at the end when she's looking at the wall of her flat and she's still got photos of her ex on the wall. She sings like she is trying to be strong but inside she is still in in love with him.