Why is my ex latching onto me?

She pleaded for us to be friends 2 months after our break up. After being together so long & her destroying me hurting me so badly i was very wary & unsure of this. But now she just wont step back or leave me alone. I want to take it slow so i havent given her my number so we talk via facebook but everyday she mails me then the moment she finishes work she mails me again. I dont understand why shes latching onto me so much, when we speak its awkard & i dont enjoy it + i still cant help but hate her for all shes done to me