Rebuilding trust after betrayal is a slow process that requires effort from both people. The person who broke trust must take full responsibility without making excuses, show genuine remorse, and consistently demonstrate trustworthy behavior over time. You need space to process your feelings and the right to ask questions or express anger. Trust is rebuilt through small, consistent actions, not grand gestures. Set clear boundaries about what you need to feel safe. Consider couples counseling or individual therapy to work through the betrayal.
Remember that forgiveness doesn't mean forgetting, and you're not obligated to rebuild trust if the person isn't willing to do the work.