I absolutely LOVED this.
Shades of "Cry Me a River."
The emotion just DRIPS off of every word, every line, and the song as a whole.
Now, if you take this gripping, harsh emotional song and set it to a contrasting very pretty piece of music to contrast the music with the lyric, this could get special.
OR... make it hard rock/metal/thrash and just scream it out. My preference would be option one, but either would work.
One suggestion... somewhere, preferably near the end, just drop an obvious, but subtle hint that if you (the singer/narrator/songwriter) were REALLY over this person, you would not be so bitterly angry. The singer/narrator/songwriter is NOT over the person being sung to. Not by a long shot.
The singer/narrator/songwriter has NOT "moved on with his/her life" and is NOT on the verge of doing so. The whole tone of the song says "has not moved on with his/her life" in spite of stating that now he/she can.
Just drop a hint that acknowledges this to the people who read (and/or listen) carefully, and the song will be WAY more interesting to those people (the people who read and/or listen carefully.)
Great lyric imo.