Your anger definitely is understandable. You have been betrayed. The fact that you are even thinking about forgiving is a good step. I would recommend two initial approaches. First, commit to doing no harm to the one who is trying to harm you. Second, with this commitment in place, then try to have a conversation with the one who is spreading the rumors. Try to get fairness from this person. In other words, forgive and seek justice at the same time.
Learn more at Why Forgive?