"Used To Be The One" by David Guetta is a song about a relationship that has turned toxic and abusive. The lyrics describe a person who was once loving and brought pleasure and happiness, but has now changed for the worse. The protagonist is being mistreated and the person they once loved has become a source of pain and frustration. The song encourages the protagonist to take control of their life and break free from the toxic relationship. It emphasizes that it is their right to leave and urges them not to wait for a better day, as tomorrow might be too late. The lyrics highlight the importance of stopping the pain and reclaiming their happiness. The chorus repeats the message of letting go and taking back control, emphasizing that only the protagonist can stop the pain they are experiencing. The song implies that although the love may still exist, it is no longer healthy and it is time to move on. Overall, "Used To Be The One" addresses the emotional turmoil and the battle to overcome an abusive relationship. It empowers the listener to recognize their worth and take the necessary steps to remove themselves from a harmful situation.