Trust. It is the foundation of any relationship. There are few things that can break the trust in a relationship as well as cheating can. Now, is cheating a deal-breaker? Not necessarily. It certainly doesn't have to ring an end to a normal healthy relationship.
Have you been cheated on? Before you end your relationship, it is important to think carefully and consider the circumstances. Consider your partner as a whole. Is he/she otherwise honest? It won't be easy, but if you trust your partner and feel that they are truly remorseful, you may want to consider working through the infidelity to keep your relationship.
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But what if they have a track pattern of infidelity and other dishonest behavior? If so, you first need to decide if you are willing to stay. If you do decide to stay, it is important that both you and your partner are willing to work together to get to the root of these issues. Sit down together and establish game plan, such as couples' counseling. Know that if they cannot be open, honest and willing to admit that there is an issue, counseling won't be effective...and their dishonest behavior is likely to continue.
While considering your partner, don't forget to consider yourself. Think about how being cheated on made you feel. Can you forgive them and let go? If not, that is perfectly okay. Think deeply about yourself and the principles that you value and live your life by. You might feel that this is the ultimate betrayal and that you cannot stay with your partner. There is no point in staying in a relationship if you know that you won't be happy. If you decide to stay, know that your feelings of hurt, betrayal and disappointment will fade with time as long as both you and your significant other work together to rebuild the bridge of trust that once bonded you together as a couple.