Just a thought. Sometimes when I have an experience like what you suffered through I write a loooooooong letter and let it all hang out. Betrayal, hurt, after all I did for you... you done me wrong. You selfish bastard! Curse his ancestors, wish that he would fall in a hole and fall straight to Hell. Be imaginative.
Get it all out.

Then burn the letter. Watch it go up in smoke and try to let your pain evaporate and float away and fall to ashes. Have a ritual like this helps release the bad feelings. Another thing I’ve done is write the name of the person or group that hurt me and abused me on a rock. Then I go to a river, lake, or the ocean and throw it in. I find it very cathartic.