They're both convincing themselves that one another is cheating in their relationship. They're questioning themselves, and believing their paranoid lies. Also, the lines "Sometimes the beauty starts to die", they're attraction they once had for each other is now fading. What they see of each other is not what it used to be. Perhaps the boy saw her as beautiful, but now that he thinks she is unfaithful, he sees her as ugly, the same goes for the girl.
They're both convincing themselves that one another is cheating in their relationship. They're questioning themselves, and believing their paranoid lies. Also, the lines "Sometimes the beauty starts to die", they're attraction they once had for each other is now fading. What they see of each other is not what it used to be. Perhaps the boy saw her as beautiful, but now that he thinks she is unfaithful, he sees her as ugly, the same goes for the girl.