Lonely and broken-hearted!!

(Venting) Breakups are so hard, but I know that he is no good for me!! I can usually get to a point of going about 2 weeks without talking to him, but then I miss him so much and either he calls or I'll call and everything seems good for the first few days, and then he does something to remind me why I left in the first place!! Each time I tell myself that this will be the last time, but it's so hard to just completely cut someone off  who you love so much!! How do you get to a place of being content with it being over?? and not going back!! Am I just weak or is this normal!! I'm so tired of feeling like this, but I continue to put myself through it!!