Hi Fallyn,
I feel for you, but I have to agree with UI on this one. Forgiveness is not really meant to absolve him from responsibility for his actions. That forgiveness you've tendered is for you. It's always harder to have seen the idol's clay feet lobbed at you rather than just observing them passively... If that makes sense.
It strikes me that if he has been pulling the same stunt on various occassions, and then repenting afterwards it is a sort of abuse of your friendship as such(regardless of its previous guise that is). People that abuse their spouses often do their dastardly deed and then apologise profusely to get sympathy and therefore forgiveness. It occurs to me at least that although this may not be a physical assault on trust it certainly is in terms of the emotional - i.e. friendships etc - life.
Anyway, just my two cents, take care of yourself. Forgive if you feel the need. Also, feel free to be angry about what he has done. People don't change if they don't realise that people will eventually call them on their behaviour. Speak to him about it. If it makes you feel any better it's like harsh medicine, the reality of his unintentional impact on those he supposedly cares about should force him to take stock, and react possitively to change. Who knows.
I've known those that refuse to make the change, they've been cauterized from my life, we all need to keep ourselves healthy - upstairs - or get healthy.
I've just realised I prattle rather alot. Anyway good luck.