She said, maybe you changed.

I'd been mumbling about reasons and the I don't know why or how's. I didn't set out trying to hurt someone, but the end result of my actions is that I did. 

So she said, maybe it's really as simple as that. It was something you needed in the past, but you've grown. You're not the same person anymore. 

And maybe if it was a different person, he could have grown with you and followed you on this journey. But he's not.