Because I'm the worst you've ever known, perhaps. So I might not hurt you, again. I'm glad that I had you, once.

Until you meet your truly happiness; with no me in your life.
You've done so much for me. Thanks a million.

Sorry as I have no sense to keep us alive, again. Sorry that I'm really too far to touch your heart.
Sorry as I'm no good for you.

But;
I'll keep 'us', until then.