Why can't Metta help end my rumination on past relationship failures?

The overthinking is a continuous circle of analysing past relationship failures and breakups which contributes to my depression. I have a very difficult time letting go. Will Metta, by actively directing compassion to the "difficult person" help me eventually end the rumination cycle and get emotionally over it? My name is Meera, from Bangalore. DOB: 26th February 1994. Time: 9:40 AM.