"I thought you would be the one who would have stayed." - He Thinks.
Dear boy, did you honestly expect me to stay when you gave me 1000 reasons to leave? People do not stay in your life if you constantly show through your actions and your words that you do not want them there. Sooner or later, that person will get the message and they will be gone. They will find someone better, someone who appreciates their flaws and does not see them as what they are: flaws. They will see it as a blessing.
You'll regret it. Maybe not now, maybe not in a year. But you will regret it, that I can guarantee you.