How to forgive betrayal?

After you have been betrayed by your friends, can you forgive them? I mean, my friends had been using me to solve their problems and all their schoolwork for some time until i got really mad and spilled the beans. They have been having a complete disregard to my pions, opinions, necessities and desires, an utter lack of respect for my property (one of them dropped my ipod and ruined its hard, but i didn't ask her to pay it due to her material status, another surfed the internet from my phone and i got a bill of approximately 400 dollars, and all this without asking my permission first). i am usually an understanding person, altruistic, that gets very easily attached to other people. I have done so many things for them only because they were my friends and i cared about them. But at some point they started criticizing my lifestyle and the fact that i did not want to join them in their "adventures" - smoking, doing drugs, having boyfriends out of pure interest, and so on and so forth. they were the persons i would open my soul to, only to have it thrown in my face now - they told me that if i do not plan on taking my life on my own hands and not mind what my parents say, i should not come complain to them when they forbid me to go out or take the car for a spin. So i decided to take a step back and become less involved, and i became more reserved with them. that was when they started talking behind my back when they thought i was listening to music and i could not hear them. when i confronted them about this they replied: "we have been talking behind your back because we have what to talk about"... obviously i asked them why couldn't they come and talk to me about the problems they thought i had and i got no answer. i have been so mad since and i really need closure... i want to forgive them but i do not know if i am such a good person. i do not want to make up with them because that would only mean me apologizing and i do not plan to apologize for wanting to be treated with dignity and respect. what would you do? i cannot help but feel fury whenever i think about them. Please, tell me your opinion, because these feelings make me a bad person. how can i forgive them?