When I tell you that you are no longer my problem, I really mean that you are no longer my saving grace.
You were, by far, the best part of being me, but I wasn't being me when I was with you.
I was letting you save me, be my saving grace. And that just wasn't right.
I need to be my own grace. Otherwise I'm not worth the grace that it would take to save my graceless ***.
Some people change you, some people too much. Sometimes you need to let those people out of your life in order to rediscover yourself and become who you were before they "saved" you.