For me, the meaning is about having a boy who you're casually seeing, who you develop feelings for, but he is too busy enjoying having no commitment to you. And even though he likes you. He doesn't quite like you enough to start a relationship. So he's running around having the same casual relationship with lots of girls, breaking all their hearts. And you eventually get the strength to leave him, even though you could carry on seeing him casually, you realise it's not enough for you and it kills you walking away when you have him (even just a bit of him) but you know it's what you have to do. Then after you give him some space, he decides he wants you back. But you know it's not a good idea, because you'll fall straight back in love with him, and he's never going to treat you right!