Someone has done you wrong.  Defend yourself, and make what changes need to be made to prevent it from happening again.

Then, let it go.  Put it from your mind.  Forgive, or not - but stop paying the person, and their actions, attention.

Your resentment is hurting you, not them.  It's costing you attention and happiness.

However you can do it, move your focus somewhere else.  And move your focus away as many times as you need, until your resentment fades.