Train yourself to default to forgiveness. If someone offends you or if they’ve wronged you, have it planned ahead of time that you will forgive them. Rise above your circumstances.
If you hold a grudge, it’s only hurting yourself. Let go. That doesn’t mean that you should forget what happened. But you should use what you learned from that experience and move forward. You may trust someone less, but holding hate in your heart will slowly destroy you.