Understand That Hurt Feelings Are Natural
If you've been cheated on, overcoming the sense of betrayal that accompanies infidelity is difficult. If your partner was dishonest regarding your relationship, what other aspects of your life, like your finances, your career, or your health could also be affected?
Conversely, if you were the one committing the infidelity, you need to recognize your responsibility for the current situation. You may try to justify things by saying that your spouse "drove" you to your actions, but the fact remains that you acted on your stress or desire. Blaming your partner for your actions will only diminish your trust in each other and reinforce whatever problems previously existed in your relationship.