Summarize the following:
What drove you to betray your partner? You are responsible for your actions, but understanding the emotion underlying your behavior may trigger your partner's empathy and will help you avoid similar situations in the future. Describe how you felt and then describe your behavior. For example, "I felt insecure in our relationship and sought attention from others."  Use "I" statements to avoid inadvertently making your partner feel like you are blaming them. It is key to help your partner see how you will avoid hurting them in the future. Identify what led to the behavior and ways you could have avoided the situation. For instance, if your behavior was influenced by a certain person, commit to avoiding being alone with them. This may involve making sure you have your partner or another friend accompany you to events the person is likely to attend, and leaving if you find yourself alone with the person.  Communicating and resolving your issues with your partner should always be included in the plan. Express genuine regret and remorse for betraying your partner. Your partner is more likely to trust you if they believe you will act to avoid future unpleasant emotions as a result of your behavior. Avoid making promises you can't or don't intend to keep. Failure to follow through on promises may make earlier apologies seem insincere.
Explain your motivation to behave the way you did. Plan to behave differently in the future. Be sincere.