Not easy to let go....

I would write him (Kevin) a letter, telling him everything that you have just said, how much he hurted you, and how far you became dependant of him. Even if you don't send it, it will remind you everytime you feel like going back to him, how much he's no good for you. Or maybe you just need to look at yourself in the mirror, and think of what you need to change to stop being so self-destructive and dependant in someone. Find something that will you feel independant, something you love for yourself. Step by step, slowly you'll become happy with yourself, and you won't need anyone to be happy. You're partner will only be there to ADD to your happiness no make it.

Good luck