Infidelity happens for different reasons; only you will know if you want to continue in the relationship if you’re the victim of a partner’s infidelity. Many people believe in the saying “once a cheater, always a cheater”, but just as many argue this. Most who have engaged in extramarital affairs in otherwise happy marriages, have felt ashamed and remorseful for their behavior. Many even told their partner about the affair, and worked to repair the relationship. After something like this happens, the most important goal is re-establishing trust, where therapy is very necessary. Also, trust your instincts. If you find that you still can’t trust your partner, have high anxiety after a long period of time, or you just don’t think you can go on in the same way, ending the marriage may be the right thing.
If your husband or wife is unfaithful to you, it can make you feel worthless. You must remember that you are an individual created in the image of God, and worthy of love. You cannot believe the lies that may enter your head that tell you that you're "ugly" or "worthless" or "not worth love" - this is a lie and you must seek the truth about yourself.
It´s a hard time. You feel a lot of anger and sadness. It´s good if you distract yourself. See friends that cheer you up a little when you can´t stand the pain any longer. Discuss the reasons with your partner and decide if you want to stay with him/her. If so you might need some professional help.